Married, and it's the best thing I ever did. Money, companies, and everything else comes and goes, but it's important to have someone who will always be there.
That said, it affects your ability to do a startup, because you have something that's more important. Oh well, I wouldn't trade it for anything!
I wouldn't either, but being really honest, I'm not as sure as you are about it. Being a successful entrepreneur, being independently wealthy, and being free to spend my life how I see fit has been a dream of mine since before I liked girls (and that was quite early). My wife is aware of how I feel and I picked a good one, so I'm fairly certain I can have my cake and eat it too. It remains to be seen if that's true.
I view being married to the right person as a more fundamental building block in "the life I want" than being rich, which is sort of a crap shoot in any case. At Linuxcare, we were probably a month or two away from an IPO on the heels of VA Linux (I was probably looking at good 100's of thousands, if not a million or two, had the market remained at those levels). Then the market turned, and the company folded (partially because they did some other things wrong, like hire some really slimy individuals). Easy come, easy go, as they say.
That said, it affects your ability to do a startup, because you have something that's more important. Oh well, I wouldn't trade it for anything!