Of the big four..
Hatton v Floyd
Cotto v Margarito
There's a shatload that everyone has mentioned so I'm going for the strange ones i'd personally like to see...
Andre Berto v Paul Williams
Amir Khan v JCC jnr
Young Muttley v Junior Witter
Jamie Moore v Roman Karmazin
Kassim Ouma v Cory Spinks

God there's millions, it makes me depressed because there's just so many we're not going to ever see.