I had no idea what I wanted in a bike until I went and drove theirs.
After my course I sat on close to 50 types of bikes - I did limit myself to under 1000cc engine... Different makes, engine sizes, years, everything.
The one I ended up getting felt the most comfortable, the balance is good, and I can push it around.
I went for a bigger engine partly because I do mostly highway driving, but also because that was the engine that came on the bike that fit me best.
Have fun shopping!
