first off, never think that you're buying too many towels. My current arsenal of paint-worthy microfibers numbers about 60 right now and at times I don't have enough. if you include crap towels that i use for engines, wheel wells, etc etc, well, i'd say over 100 easily. You'd be surprised how many towels you can fit into a large rubbermaid bin
i'd suggest something along these lines to get you started-
3-4 cobra super-plushes for quick detailing. These are awesome towels. very thick and squishy!
3-4 cobra gold edgeless polishing cloth. I only recently picked up a few of these, but i must say, they make product removal a breeze!
1 cobra green all purpose towel 6 pack. these are good for anything from QDing to product removal to waterless washing. they truely are all purpose.
maybe pick up a small glass towel or two. The new cobra ones give me no streaks. Works wonders with the DP krystal vision glass cleaner
that should give you a good start!