PS and what he said
Not sure about the sizing on the used bikes you've posted - I'm a little over 5'11" and most seem on the small side for me, YMMV. That Jamis looks nice but that one looks like it would probably be too big for your size? I would say you should get properly measured first either at a shop you trust or if you want to go internet or using something like the
Competitive Cyclist calculator.
For online stuff, although I've never bought one the Bikes Direct bikes seem like a pretty good deal, those Motobecanes look pretty decent, of the ones you listed - maybe the Super Mirage? If you wanted to go the Hybrid route, the Fuji Absolutes from Performance ride nice can be a good deal. My girlfriend bought an ABosulute 3.0 last fall, which she's happy with.
Realize if you buy bike online, there very likely may be some minor setup and adjustment which you'll either need to do yourself or rely on LBS.