I'll second Al's recommendation to look at the Bogen/Manfrotto line of tripods. They're worth every penny you pay for them.
Before you start searching, though, figure out how much weight you need to support. Look up the weight of the camera and the longest, biggest, lens you're ever LIKELY to put onto the tripod and then spec your purchase based upon that, plus a fudge factor of a "little bit" just to allow for any eventualities.
Yeah, you might be able to get sharp images with a tripod/head combination that's rated for less poundage than you're applying to the combo, in perfect conditions, but...
Happy shopping!
Bogen/Manfrotto web site