Alzo Digital 5500K 91CRI Compact FLuorescents.
( I recommend knowing what CRI is before you buy more bulbs. )
I am still amused by the possibility of gelling a 100 CRI ~3100K halogen to 5500K.
I also really want CIE Illuminant E emulators for lightbulbs. An equal energy radiator. Flat spectrum. Imagine the color separation.
Update (2010-07-15): Some buzzing is apparently normal for this batch and "is something we need to address in our next round of bulbs".