As long as you stay with a solid name brand (Colt, S&W, Ruger, etc.) it really doesn't make that much difference. The most important thing (IMO) is to select one that fits your hand the best, that you're comfortable holding and firing. And if it's also going to be a concealed carry weapon, then I wouldn't get some magnum hog-leg that is all but impossible to conceal.
Best bet: go to a firing range that will let you rent various brands and calibers. Try them all out and see which one best suits your hands. Unless I've had friends that owned something I was considering, that's what I've always done.
Personally, I wouldn't get anything in a .38 ... a .357 magnum, maybe. But that's up to you.