My main beef is flash, and just general instability lately, I stopped using it a month ago (I dual-boot windows for games and some peripheral gadget syncing) and I'm going to give it another go at the end of the month with 12.04.
I still am not sure if I am going to stick with linux, because I just can't get away from a few programs, and wine doesnt cut it, I need usb support. Also I've had a ton of probles with wine, and I hate the ad-hoc way it looks and works.