Sounds like you jumped in head first! You are on the right track. I like my brooks saddles, but I don't think they would make a lot of difference on such a short commute. I wouldn't go for a 60 or 100 mile ride on anything else though. The BMX platforms are a good way to start, they should last forever, I wouldn't go to clipless unless you start going for long rides. If you start having problems with flats, consider Armadillo's or Gatorskins.