I've used the cheapo $15 6 speed SIS Shimano's - 14-28 for me, and 14-34 for my wife. Very nice. I just got a Nashbar-branded 7 speed 13-32 for myself. I like it so far. Shifts almost as nice as the HG, but it doesn't have as many grooves and pins and crap in it. Finish isn't as nice as the shimano, but at least it's all the same color. I really like having 13-15-17-19-21 instead of 14-16-18-21, and the extra big 32 is kind of nice too. My knees like it.

A little pricey, but where else are you gonna find a 13T and a nice big bailout gear? I haven't seen anything. I had to add another spacer, but my axle was juuuuuust barely long enough.

http://www.nashbar.com/bikes/Product..._200276_200429