The obvious question is "why don't you put the tool kit in the panniers"? I suppose if you don't want to carry your panniers everywhere, but want your tools always available, you can get a front bag or a top-tube bag. I would pick the front bag over at top tube bag.

One strong word of suggestion about tools; skip the multi-tool gizmos. Multi-tools are really great as long as you never have to use them. You know, you will really appreciate a good tool when you are sitting on roadside gravel trying to make a repair on your bicycle. Get yourself some hand tools. The basics can come right from the hardware store - adjustable wrench, screw-drivers, pliers. Bike specific tools would be; chain tool, tire irons, spoke wrench, allen tools, cone/pedal wrenches (maybe), etc.