A gazillion and one choices out there. I've been happy with my FSA SL-K stem ($60) + Performance Forté Team Alloy($30) road bars. No not the blingiest set up on the block, but has been stiff, comfortable and light enough - works for me. Things I like about this handlebar: not too shallow; not too deep; reach seems perfect; and comfortable whether on the drops, hoods, or tops.
...but of course, a big YMMV.