I have one of the Sci-Con Elan 210 bags and it holds everything I need - tube, tire levers, CO2 inflator, two cartridges, a patch kit and a tiny multi-tool. Note that I use a little Air Chuck SL inflator and 12 gram cartridges but it all fits with just enough room to slip in a $20 bill. Sci-Con has also now come out with a carbon styled version of the same bag which is sharp.

If you can live with one water bottle you might also look at the Sci-Con Tubo water cage bag or the Soma Stash Bottle - they both fit in a bottle cage and are more spacious.