I lace, true, dish, and tension my wheels myself. I'm not saying I'm especially good at it, you understand, but I do enjoy it. Aside from enjoying it, it's just one of those things I do myself, to the best of my abilities, like cooking, shaving, and tying my shoes. Having built several dozens of wheels over the years, I have never had one fail catastrophically; once I had to rebuild with new spokes because I didn't tension properly (it was a tandem); and twice I overtensioned the spokes such that after ten years of hard riding the rims started to crack. And I've never had a real truing stand; sometimes I flip the bike upside down, sometimes I use an old fork held in the jaws of a bench vise or something.

I say go for it. It's not rocket science, and... well, when you think about that guy who laces, trues, dishes and tensions the wheels at the bike shop, there's no guarantee he's any better at it than I am.