I have the Cateye EL530: http://www.nashbar.com/profile.cfm?c...Front%20Lights
and the Cateye EL410: http://www.nashbar.com/profile.cfm?c...Front%20Lights
The smaller, cheaper one (EL410), actually has a more concentrated beam IMO. I think the 530 is overpriced for how (not) bright it is, and for the fact that it only has two modes ("high/steady" and "off"), but it does the job for my primarily city commuting where there's usually ambient light. If I'm riding at dusk and I can see fine but I'm worried about visibility, I'll just stick the 410 on my handlebars and put it on flash mode. If I'm riding in the dark, I'll put the 530 on my handlebars on high steady beam and the 410 on my helmet on flash (dorky but I think it really helps visibility)... One thing I do really like about these lights is that both of them have super easy mounts that can be installed and removed in 30 seconds.
And in the fall/winter, I keep this tail light mounted on my commute bike and put it on flash mode if I'm riding at dusk or after: http://www.nashbar.com/profile.cfm?c...0Rear%20Lights.
It's super bright on flash mode.