I would agree that it is of the utmost importance to get a bike that FITS! Once you go to the LBS and test ride lots of bikes (for free) and get lots of advice (for free), then it's time to get serious and start looking for "deals" if money is the main issue.
My advice: Get Shimano Ultegra 10 speed, or better. Be prepared to spend at least $2000 to get set up properly. And get the best set of wheels you can afford. Don't skimp.
The longer you sit on your bike and ride it, the more you'll notice the sluggishness and crappy shifting of an inferior setup. You pay for lightness and quality. Splurge!! After a few hundred miles, you'll forget about the wad of cash you dumped on your bike (you won't miss it), and you'll just feel the LOVE. If you buy a cheapo, the $500 you saved won't seem so important when every pedal stroke is inefficient and miserable. Most people who buy a cheapo bike will dump it within a few months and then spend a couple of thousand dollars on a new one.