Provide a way to clear IM chat windows. Right now the only way to clear the IM window would be to disable IM logging in the preferences and then close/reopen the IM window when you want it cleared. Pidgin has a "Clear Log" feature using CTRL + L or Menu > Clear Log.

I find it really useful at work when a nosey coworker wanders by or a friend IM's you something they shouldn't when the boss is right over your shoulder.