We use these
http://www.superbrightleds.com/cat/f...rips-and-bars/
And get blue/red/white.
The white we hook up to the PDB so it's always on, and it's in our chassis to illuminate it. The red/blue we put into any type of mechanism we have and they're both hooked up to spikes. We have a light switch that goes to a Digital I/O port that way programmers don't recompile code each match, we flip the light switch one way and its red when the robot is enabled - other way blue.
As an added bonus, turn both lights on for autonomous and since they're right next to one another, it turns it purple.
http://i.imgur.com/z9lww3N.jpg They look pretty snazzy and gives a different effect from all the other teams that mostly light up at the bottom.