I highly recommend the TLR 1 from Streamlight. The fit is nice and Botach Tact has them for 85 bucks as 2 weeks ago. Ive seen them for under 100 a lot. Also its LED so the battery time is a bit longer. Alos you can later set them up with a pressure pad if you decide to move the light to a long gun.
Note as of 5/28/08 at 1709 the light was still 85 from botach
As soon as my stimulus check gets in I'm getting an M6 light/laser from Insight Tech. for both my HK USP 9mm and FNP-40. I'll need an adapter for my HK but not for my FNP-40. $200 for a light/laser combo from cheaperthandirt is a good deal.