One other thing I'll mention. While all the companies pretty much use the same gear set, which gear set you get at a price will vary. A lot of 21 speed gear sets have a freewheel. While they work fine, I personally avoid them. In fact, I avoid all 21 speed gear sets. The reason is your road gear. All the 21 speed gear sets I have seen have the smallest cog at "14". The eight speed (24 gear) cassettes most often have an "11".
The result is that when I'm riding with some of my old crowd (road bike riders), I the 21 speed bikes are just geared too low and even big ring, small cog I'm spinning to beat hell to try to keep up. I at lest have the gear to keep up on the 24 speed and 27 speed gearsets.
While I suggested to check out the Trek FX-2, that was based on the value of that bike right now (compared to what you get in other bikes at the $400 level.
Test rides, so far, I like the Giant Escape and the Cannondale Quick. Problem is with the Cannondale, you might have a problem finding a dealer ( my nearest is an hour and a half away) and they tend to be a bit more expensive for the features you get.
While it rode mountain bikes back in the day, my love was always road bikes. I put tens of thousands of miles on road bikes before I destroyed my knees. Now I have an upright comfort bike, and I hate it! Because it feels most like a road bike to me, I have decided I really want to get a Cannondale Quick 4. Of course the problem is that model is $700 and I thought I could afford $500. The one bike I really liked was the Giant escape. But the model with the carbon fork is almost $700 too. They have a great model, I think it's the Escape 2 that is about $429, but after riding several of the carbon fork bikes, I decided I will be getting a carbon fork on my next bike.
Of course the way you fit the bike and the way the bike feels is the real way to decide on a bike. You really need to spend some time doing test rides. For me, the fact that I have an Uncle and a nephew that bouth have Cannondale and I have had a chance to ride the Quick 4 for a whole lot more then the short rides you normally take for test rides. This weekend, we are meeting again at a bike ride, and I will get a chance to put some miles on the bike with a spring fork. This is important to me, because mt current "comfort" bikevhas the spring fork and I really don't like it. But I'm guessing it's because it's a cheap fork and I really feel it upsets the frame and, on my bike at least, makes it feel "twichy"