I just got one of these:

On flash mode, it's so bright I won't use it when I'm riding with other people. I just wish it had better mounting hardware. Right now it's clipped to my seat pack and hasn't fallen out yet - I'll have to jerry-rig something to get it onto one of my oval seat stays (there is mounting hardware for a round seat stay).
ETA: I also just got one of these
- haven't worn it on the bike yet, only for running (hardly notice it's there unless I want to take a jacket off) - but I really bought it more for riding than running because of all the reflective material.
Last edited by OakLeaf; 04-13-2008 at 05:30 AM.
Speed comes from what you put behind you. - Judi Ketteler