And while you're buying some UX1K Luxeon-III's, don't forget about the $4.95 Luxeon-V's (bin VX0U) that are near the bottom of ARC's accessories and modder parts page...
VX0U Luxeon-V:
V = brightness of 113.6 to 147.7 lumens
X0 = pure white tint
U = Vf of 6.87V to 7.35V
The relatively high Vf is perfect for direct drive or simple resistor applications. They would be perfect for direct drive on 6 NiMH cells (7.2V) in a 2D M@gMod using a couple of inexpensive 3AA to 1D battery holders; or use a low ohm resistor for direct drive with 2 Li-Ion cells.