shop the bike shops, every one of them will tell you thiers is the best, fit you up and let you test ride.
Mostly depends on what you want out of the bike.
I recently bought a Trek Navigator 3.0 " hybrid" cruiser style just shy of $500, I got the more expensive verison ( compared to the 2.0 ) due to the heavier wheel construction, which is something of benifit for my size.
if you dont want to buy used by a last years model from a bike shop i saved like $300 that way and i recomend giant i have put about 2000 miles on it probably in the last 3 years but it is a mountain bike just get what ever you are comfortable on
I got a full carbon Motobecane from Bikesdirect.com. I've got 2600 miles on it and love it, but at the time, it was $1900, there are much less expensive models on that site.
I do see a decent amount on craigslist for Winston and Greensboro, might pick up a good deal, so long as it's the right size.
Used MTB is one thing... used Road bike... not me.. they're just too fragile and unless you can go pick it up and inspect it... you can easily get screwed..