I just bought my first bike, a Specialized Sirrus Comp, which I plan on using for primarily for fitness and commuting. My plan right now is to get up in the morning and hit the road to build my fitness level up and once I'm in better shape start riding to work which is only 6 miles but it's all up hill from my house.

My bike came with a Cateye computer and water bottle holders, but what else do I need to have it ready to tackle all season riding and commuting? For instance, do I need to get a under seat tool bag, front and rear lights, pumps, fenders...the list goes on. If your bike was bare what you purchase right away? Thanks for your input.