Ideal Hybrid for Heavy Rider?
I'm looking to buy a commuter bike (~3 miles each way), but have never ridden anything other than a mountain bike. As such, I thought a hybrid would be the perfect mix of something I find comfortable, yet is equipped for the daily ride. I'm realizing my price point (~$200) is fairly low for a hybrid - even used. I live in Philadelphia, and there is a plethora of craigslist posting for used bikes, the most of which are road bikes (with the lean-forward handle bars/breaks). I'm guessing that hybrids are a fairly new concept, as I don't see any 70s/80s postings like I do for road bikes?
I'm 6' and ~220 lbs. What sort of tires and frame (as in material) would a person of my build be best on? Can anyone make any recommendations as to older Hybrids that I might find in my price range? A friend also said that I could probably convert the handle bars on a road bike to up-right bars, but I'm guessing that involves more experience than I have.
According to the charts, I'm best on a ~56cm frame. I thought that seemed a little small for someone 6'...
I've been seeing a lot of talk about the Giant Escape 3, which is about my price point, but I might be able to find used if I hold out..
Thanks for any advice!