I went to walmart a got some of those lights too. not bad for the price. but they weren't bright enough.
so i decided to spice it up a lil.
I bought 4 luxeon III, 2 15deg flood lenses, 2 5 deg spot lenses, a buckpuck, a heatsink, and a switch.
long story short I converted a 50w 360lumen (29candle power)floodlight to a 12W 500lumen (40 candle power)spot/floodlight
this thing is BRIGHT!! I crammed all 4 led and lenses into the housing so 2 leds act as floods and 2 act as spots
I'll do a writeup if i end up doing the other side.