I commute to work every day, 25 miles round trip. As far as tools, I carry my multitool, spare tube, patch kit, co2 pump + cartridges, and a 15mm wrench when I ride the Sputnik. I haven't really needed anything else so far. I once had a shifter cable snap on my road bike that left me stuck in the highest gear for around 8 miles.. uphill.. I didn't have a tool with me to fix it.. that sucked..

I generally check my bikes from time to time when i'm at home, so if there are any problems, I can take care of it before I get out on the road.