My bike doesn't have too many bells and whistles attached (though now that I think about it, I should get a bell...) Here's what I've got:

*2 water bottle cages with water bottles. One's a Polar bottle. The other was free with the bottle cages from the LBS.
*Seat bag, containing two spare tubes (well, until recently--I need to get more), 2 CO2 cartridges, and I have a mini first aid kit, multitool and tire irons on order (c'mon, postal service!)
*rear tail light (got lost in the move, it's in my room somewhere)
*cyclocomputer.