Well the second one (specialized) has more potential as a commuter, but doing it from scratch like this will be harder, probably more expensive, and take longer. Could be more fun, if you are mechanically inclined and can figure out the cycling specific stuff.
Example, the seller says he's including a 1 1/8 threadless stem, and you can convert the frame to take a threadless headset. It's not specified, but I assume this means that the original fork was 1 1/8 threaded. That being so, you can take his advice and convert it, then use his bar and stem, or find a threaded fork of the same size, and use his bar only, plus a quill type stem.
Here's a good link to get you started, the Late, Great, Sheldon Brown.
http://www.bikeforums.net/showthread.php?t=253025