About $200. I'm big on premium software also, and not much so on games. Some apps I bought which I don't regret are:
Navigon - 70
ToDo - 10
Beejive - 16
Newsstand - 5
Billminder - 1
Radarscope - 10
Docs to Go Exchange - 10
Flight Track Pro - 10
Zagat - 10
Starmap Pro - 19
Wunder Radio - 6
Tweetie 2 - 3
The only purchase I regret was Sims 3 when it was 10 bucks. I played it like for 10 minutes and never got into it. From then on I told myself I would never spend 10 bucks to buy games.
Pano ToDo was $10, which I feel like is crazy, but I got so fed up with the free to-do lists that crash and freeze that I just gave in one day. TouchPad
My brother has bought several little apps, some of which I use.
I have some that were decent amounts - the most being Pocket Informant. But i use them so it's ok.
Most of my $$ stuff is still installed - except Monkey Island, i needed the room one day. I need to put it back on so i can play it in my spare time. Of which i don't really have any at the moment.....