I got killed on AMT because of stock options. I then found out that most CPAs don't know how to deal with AMT or how to retreive credits in future years.

Try Fairmark for a discussion of the topic

And ReformAMT for more opinions

Anyway, I thought you could write off up to $250k ($500k if married) gain on a house if it was your primary residence for 2 of the last 5 years...?

I can vaguely remember my tax class back in college, where we did AMT calculations and returns. I would check with an enrolled agent or CPA specializing in tax issues about this.