Sounds like you got it pretty well figured out. Just start riding and you'll figure out what you need. I have about the same length of commute and it's do-able, but not necessarily every day, at least to start. Having a shower at work makes this possible; without that, I would say it's too long of a commute (I used to do a 7 mile commute with no shower, but 17 miles each way would be too far, at least for me). I carry stuff to and from work (as opposed to taking it by car the day before or whatever). If you plan to do the same, you're key piece of equipment will be panniers. They weigh the bike down a bit but that just adds to the exercise, right?