I say "Go for it, buy that 29er, you only live once", but alas, I don't live by that guidance myself. Maybe in 12 years when the mortgage is paid and the (three) college/wedding accounts are funded well, and the oldest is out of the house, I can begin splurging on myself.
Unfortunately that means I'll get all those "Oh, he's in his mid-40's, must be a midlife crisis" remarks, but I guess you have to live with it. I'd go cry to my mom that people are picking on me, but she'll be the first in line with the jokes! Haha.