Hellmuth annoys the crap out of me most of the time, but then I remind myself that it's his "schtick." He reminds me of the villain wrestlers from my youth, before it became all Hollywood -- their job was to incite the crowds and get people in the seats. Hellmuth is a great tourny player (not so much ring player, apparently) but he plays the brat role to the hilt. Hearing those who know him personally say that he's really not like that in real life convinces me that it's an act, and one he excels at, so in that regard I have to get him credit.
Personally I don't care for Corey Zeidman either, he comes off as some kind of GQ wannabe who is a great stud player but cares more about the "celebrity" status of Hold'em. I will admit though that seeing him and Hellmuth go at it on PAD was funny as hell, Corey really dug into Hellmuth and totally threw him off his game. And Zeidman gets a lot of grief for allegedly slow-rolling Jennifer at the 2005 WSOP, although personally I didn't see it as a slow-roll, just his being annoying as usual.
And Mike Matusow is a different kind of obnoxious. He's more like the lovable goof or fat best friend that everyone likes to pick on, but ultimately would do anything for (and he them). He doesn't bother me at all, I find him fun to watch. Sometimes I actually feel sorry for him, especially after hearing some of the other pros telling their Matusow stories.
What I've seen of Tony G would have to rate him pretty high on my annoyance scale, he's way over the top even for show.
I've only seen Humberto play a couple of times, and while he came off a bit corny or silly, I don't remember seeing the sort of behavior you guys are talking about. Guess I need to go catch up on more of his play.
EDIT: Oh yeah, Tom "Durrr" Dwan has to rate pretty high on the annoyance scale as well. Something about his effeminate manner and voice just grate with me.