I use a wedge pack that is just enough for the emergency tools and tube, but I also use a Camelbak that can carry some other items.

I ran into someone on a group ride a few days ago that was using a bag found at a military surplus store as a saddle bag. It was a fair amount bigger than most seatpacks and tucked up under the saddle nicely.

Another option I sometimes use if I am not wearing a jersey with pockets, is one of these small top tube panniers