I want to be able to get root access, get rid of carrier-installed crapware, maybe even check out some custom roms. At the moment, I can't even install Cyanogen on this thing...
Look for Cyanogen 7 - they may have come out with a version for that phone. Also ask on Area51 Forum - some of those people still play with the older phones (and wrote ROMs for them back in the day).