I've only been biking a max of 20 miles (usually shorter) so far this year with the cold temperatures, so I currently carry one water bottle, my cell phone, a frame-mounted hand pump, spare tube, levers, patch kit and multi tool. I also wear a RoadID if that counts as carrying, but it's attached to my LiveStrong bracelet and actually never comes off.

The hand pump seems kind of worthless. I've only used it once so far and after pumping until it seemed like I couldn't get one more molecule of air in the tire, it only registered at 40psi on my air gauge. I can't imagine I had it hooked up incorrectly, but maybe. It's just a cheapy from Bell. I'm thinking about switching it out for a CO2 cartridge. Also, when it warms up a few degrees I've got some 40-60 mile routes planned, so I'll probably add a second water bottle.