Hi everyone!
I stumbled across the forum today and have really enjoyed reading all of the helpful advice I've found so far. I hope you don't mind entertaining another "help a n00b buy a bike" thread...

I did a fair amount of biking around town when I was in college at the University of Wisconsin (in Madison, a nice, bike-friendly city ). I was riding a cheap-ish sporting goods store mountain bike that I bought in 8th grade. Yikes. I doubt it was anywhere near the right fit for me, as anytime I rode the thing carrying any little bit of weight in a backpack or messenger bag I felt like I couldn't breathe. I do have a history of some orthopedic problems (chronic yet unpredictable knee, back, and hip pain, and scoliosis, probably all stemming from having one leg that is significantly longer than the other), so I'm definitely looking for a GOOD fit this time.

Anyway, I just moved from Madison to Tucson, AZ (also lots of bike lanes--yay!) for grad school and sold my old bike to a friend before I left.
I'd love to get into road bikes but don't feel quite confident enough in my riding skills to do the super-skinny tires and drop bars yet. Cyclocross is budgetarily WAY out of the question. I don't really see a need to have a mountain bike again, since my riding will probably be exclusively on paths and paved city streets.

So that leaves hybrids, eh? I visited a couple local bike shops yesterday and rode a few. I was very taken with the Bianchi Cortina, but my boyfriend has had no small share of problems with a kind of bottom-of-the-line Marin hybrid that he got a couple years ago... different brand and all that, but his negative experience buying from the "cheap" end of the spectrum of a "good brand" gives me pause. The bike shop guy also suggested the KHS Urban-X, but didn't have one in stock.

I'm drawn to the Trek WSD models, especially since I have small hands and am more on the leggy/short torso side. The 7.2 FX caught my eye online (I definitely prefer the look of a straight top tube to the staggered tube or curvy business), but I haven't had a chance to make it to any Trek stores yet to ride any. That one's also more expensive than the two I mentioned before.

I guess what's scariest to me is I know NOTHING about components. I know Bianchi is a respected name in bicycling, but for all I know the derailleurs on the Cortina could be made of tin foil and chewing gum.

Are there any good resources online anyone can suggest for educating myself on bicycle components? Can anyone help me out and tell me how things compare on the Bianchi, KHS, and Trek models I've linked above? Would anyone care to suggest another bike in the $500-or-less ballpark? Is anyone still reading this really long post?

Many thanks! I look forward to any and all opinions, and to reading lots of posts on this awesome forum for a long time to come!