If AIM won't let you toggle real name or whatnot, you could switch to Trillian, which has almost all the features of AIM and does indeed let you rename your buddies, so if you wanted, you could have both, say, "kirkjerk - Kirk I."
Yeah, and not to sound too fussy, but I wasn't crazy about the sound set Trillian came with.
Far and away the best 3rd party msg software I've seen is "Adium X" for Mac. For starters, they even have the AIM soundset as an option!