Because we were ready to move and didn't want to hassle with renters while on our cruise that was projected to last between 6 months and 3 years (ended up being a little less than 2).

I regret it for economic reasons -- we sold in 2001, just before the housing boom and lost the upside, and bought in 2004 at inflated price that now don't look so inflated.

Had we waited a few years and sold in 2005, I'd have been estatic.

But other than that, I don't have any regrets about selling it. If you like you current house, keep it. If you're planning to sell anyway, it's probably a good time to do it (putting aside speculation as to what the market might do).