Here's a disambiguation of several common opera voice types and subdivisions with excerpts to give examples. This should not be considered authoritative. Feel free to add other excerpts, as the more we have, the more can be understood.
There are a LOT of WONDERFUL performances which are not featured here, as this is the best we can find around the web for free clips
xd sweatdrop Coloratura Soprano-Gianna Rolandi sings the role of Clorinda from Rossini's "Cinderella." This aria is often cut because Rossini did not compose it; his recitative composer wrote this so is often left out to leave it authentic (and also because it's so hard). Low sound quality, and sung in English rather than Italian. A lot of improvised ornamentation. High F in last note.
http://www.youtube.com/watch?v=qlY1a5iylbs-Natalie Dessay sings the role of Lucia from Donizetti's "Lucia di Lammermoor." The famous "Mad Scene" as it's come to be known as. Flute here has been replaced by a glass harmonica, and improvised unaccompanied cadenza. Holds a high Eb as last note.
Part 1:
http://www.youtube.com/watch?v=HNqDEt8Ec38Part 2:
http://www.youtube.com/watch?v=Q_Z6B6yApHoPart 3:
http://www.youtube.com/watch?v=RKRiFph8Gek-Diana Damrau sings the Queen of the Night's famous aria "Der Hölle Rache" from Mozart's "Die Zauberflöte." High F is composed in the score. Aria starts 2:09 in.
http://www.youtube.com/watch?v=DvuKxL4LOqcSoubrette SopranoBarbara Frittoli sings the finale scene from "Suor Angelica" of Puccini's "Il Trittico." Holds a high C in the end despite an exhausting monologue
http://www.youtube.com/watch?v=KwjfEqFBFEgLyric SopranoRenee Flemming sings Donna Anna's "Non mi dir" from Mozart's "Don Giovanni." Clip includes recitative. Aria begins at 1:56
http://www.youtube.com/watch?v=yrTgxcI305k-Leontyne Price sings role of Aida in Verdi's opera of the same name. Aria "O patria mia" in her last operatic performance. Rough quality, holds high C.
http://www.youtube.com/watch?v=W6kR5ZvLN80 -Olga Mykyntenko sings the famouse "O mio babbino caro" from Puccini's "Gianni Schicchi" of "Il Triticco." Role is Lauretta, and this aria shows up in a number of TV shows, movies, cartoons, and recently in the Grand Theft Auto III commercials.
http://www.youtube.com/watch?v=QXV-SsMgSOoDramatic Soprano-Waltraud Meier sings the famous "Mild und Leise" aka "Liebestod" as Isolde from Wagner's "Tristan und Isolde."
http://www.youtube.com/watch?v=oOGs8TtnwoIColoratura Mezzo-Soprano-Joyce DiDonato sings "una voce poco fa" from Rossini's "Barber of Seville." This role is also sung by a coloratura soprano and transposed up, usually to attract soprano fans and cast a famous soprano since mezzos are not as commonly the star attraction, but Rossini did originally write this as a mezzo role. Hits low G# and high B in ornamentation.
http://www.youtube.com/watch?v=ysGFMx6NOEYLyric Mezzo-Soprano-Agnes Baltsa sings "L'amour est un oiseau rebelle" more commonly known as the habanera (a Spanish dance) in Bizet's "Carmen." Bizet took the theme itself from Sebastián Iradier's habanera "El Arreglito." Iradier's mostly known for his piece "La Paloma."
http://www.youtube.com/watch?v=px36njyCnVMColoratura Contralto-Sonia Prina sings the role of Lotario in the opera of the same name by Handel. Originally a castrato role, Sonia is performing as a trouser role (as is common now). Low F# in ornamentation.
http://www.youtube.com/watch?v=wN3Rqhmd3Nk-Cecilia Bartoli sings a transposed "Prendi, per me sei libero" fromDonizetti's "L'elisir d'amore." This is in tribute to Maria Malibran who created this arrangement, thus a formal production of the opera will not feature this excerpt. Grazes a low Ds and Es and sustains a high B
http://www.youtube.com/watch?v=JocsSqysqs4Contralto-Ewa Podleś sings the role of La Cieca from Ponchielli's "La Gioconda." Aria "Voce di donna o d'angelo"
http://www.youtube.com/watch?v=qAueXMs29IM-Birgitta/Brigitta Svenden (Different sources have her name spelled differently) sings the role of Erda in Wagner's "Das Rheingold." Erda's single scene, "Weiche Wotan, weiche!"
http://www.youtube.com/watch?v=0ddOhDxbWgU-Stephanie Blythe sings the role of the Princess from Puccini's "Suor Angelica" of "Il Trittico." Duet scene, Barbara Frittoli (soprano) playing Suor Angelica. An interesting clip as it features nearly opposite female voices.
http://www.youtube.com/watch?v=scWfWA7quY0Castrato(The practice of the castrato was finally banned in the 19th century after literally centuries of savagely castrating young boys in order to keep their singing voices high and pure for profit, resulting in other developmental problems physically, mentally, and sexually. Roles of castratti are today performed by women as trouser roles, natural male sopranos/altos, or countertenors)
-Alessandro Moreschi sings Tosti's "Ideale." The recording is extremely rough, and at the time of recording he was old and had lost much of what he was probably capable of in his age, but is the only known castrato to have been recorded.
http://www.youtube.com/watch?v=M07Qga3LbcMMale Soprano(This voice type is extremely rare. A natural male soprano occurs from a developmental/hormonal problem, and the voice does not drop as a result.)
-Michael Maniaci sings the role of Nireno in Handel's "Giulio Cesare." Maniaci has no growth or hormonal problem, but for some reason his voice never cracked (Larynx did not develop). Originally a castrato role, aria "Chi perde un momento."
http://www.youtube.com/watch?v=voZsllaIfCkCountertenor/FalsettoDavid Daniels sings the role of Oberon in Benjamin Britten's "A Midsummer Night's Dream" based on Shakespeare's play. This is one of the few roles that was specifically written for a countertenor, rather than one that was originally a trouser role or castrato role.
http://www.youtube.com/watch?v=05u-Rkvucn8Leggiero Tenor-William Matteuzzi sings the role of Arturo in Bellini's "I Puritani." Final scene featuring the chorus and soprano. Matteuzzi hits a high Db and then a high F in full voice, rather than mixed or full falsetto as other tenors often do when attempting this role.
http://www.youtube.com/watch?v=VPiHRa28XAM-Gregory Kunde sings the role of Fernando in Bellini's "Bianca e Fernando." Aria "A tanto duo" with preceeding recitative. Very rough sound quality, sustains a high F and a high Eb despite so much exhausting singing.
http://www.youtube.com/watch?v=e1nA19TvH9ILyric Tenor-Placico Domingo sings the Duke's (in)famous aria "La donna e mobile" from Verdi's "Rigoletto." Many are surprised to find out the translation. If you also didn't know: this role is a mysoginist rapist. Note the fast flourishes, holds a high B but not as strong as most.
http://www.youtube.com/watch?v=6HcrVzwlocA-José Carreras sings the role of Rodolfo in Puccini's "La Bohème." The famous "Che gelida manina" considered one of the most romantic tenor arias of all time. Sung here in the original key (it is often transposed down), and reaches a high C. Aria begins at 4:41
http://www.youtube.com/watch?v=azl8o0VuCFEHeroic Tenor-Peter Hofmann sings the fantasy-like "In fernem Land" from Wagner's "Lohengrin." The final scene of the show, modern interpretation in this production. Side note: this opera is also the birthplace of the famous "here comes the bride" theme (though that's not what it's called)
http://www.youtube.com/watch?v=1jTMtaojTzcBel Canto BaritonePietro Spagnoli sings the famous "Largo al factotum" opening scene from Rossini's "Barber of Seville." This production's setting is a more modern interpretation.
http://www.youtube.com/watch?v=9UDCmFG8OpMLyric Baritone-Cornell McNeil nails a high A in the finale of Verdi's "Rigoletto."
Short clip featuring this one excerpt.
http://www.youtube.com/watch?v=PqGdLtRJIDs-Detlef Roth with Papageno's aria "Ein Mädchen oder Weibchen" from Mozart's "Die Zauberflöte."
http://www.youtube.com/watch?v=ExnOKlnlodYBass-Baritone-James Morris sings his signature role of Wotan, finale scene of Wagner's "Die Walkure" of the Ring Cycle. The dramatic duet betweeen Woton and his daughter Brünnhilde sung by Hildegard Behrens (dramatic soprano)
http://www.youtube.com/watch?v=WnuNJFbPjzoBasso Buffo-Ferruccio Furlanetto sings the famous "catalogue aria" properly titled "Madamina, il catalogo é questo" from Mozart's "Don Giovanni." Note the flexibility and fast notes.
http://www.youtube.com/watch?v=l0lN6SJkpBQBasso Profundo-Cesare Siepi sings Marcel's "Seigneur, rampart et seul soutien." Hits a low C (short clip featuring his progression to C)
http://www.youtube.com/watch?v=RPxU6HFWV98-John Tomlinson sings the role of Hagen in Wagner's "Götterdämmerung." Excerpt "Hier sitz ich zur Wacht." Note his final note is in one breath.
http://www.youtube.com/watch?v=dZWSn6sgyJA-Matti Salminen sings the role of Fafner the dragon in Wagner's "Siegfried." In this clip, the role of Siegfried is Siegfried Jeruselum (heroic tenor). Salminen is offstage (behind the dragon/monster/whatever-that-thing-is prop)
http://www.youtube.com/watch?v=OS0bwKkXwEU