You're gonna love it. I'm in my third week of a mixed bike/bus commute, and I actually look forward to going to work. Of course, I look forward to going home too, it's just the nine hours between....

My opinions on how to carry stuff: single pannier is okay, if you can use it w/out heel strike. Backpack sucks. Messenger bag is so far the best option, but I would rather find one made to hang on the right shoulder, the one I am borrowing currently rides on the left shoulder, and slightly interferes with my view looking back to check on upcoming traffic.

Have fun with it!