Renting is simply better for me. My rent is low enough in a nice part of town, I don't have to worry about housing-related repairs, and it gives me flexibility when it comes to traveling for extended amounts of time.
I'm in my 30s and I expect I'll be looking for a new job every 5-6 years in today's economy. It's really hard for buying to come ahead of renting when length of employment in one place can be as short as that. Even if I buy a house, my mortgage would have to be low enough so that when I change jobs, I don't have to worry about running out of money for 6-9 months (15% take-home would be bearable).
As I wind down my career, I expect home ownership to make more sense form, but not right now.