I was hoping for a few specific recommendations. I'd like to keep it under $50, with AA or AAA batteries, and all contained in one small unit.

This one gets mixed reviews: http://www.amazon.com/Intsun%C2%AEQ5...I13CU1OCFU6KDS

Same here: http://www.amazon.com/Princeton-Tec-...FRGDUAZL&psc=1

My favorite so far: http://www.amazon.com/Planet-Bike-Bl...words=beamer+3

Note that this will never be used for night riding.