I really like the ATi Blue plus bulb, it's actually very bright for being a blue bulb and will accent halides.
Also a nice one is the UVL Super Actinic. While no where as bright as the ATi, it gives that more traditional "purple" actinic look, and does cause a different level of fluorescence than blues. What you could do, what I did
, was simply do 2 & 2 and have 2 ballasts and have an initial ramp up in intensity then eventually ramp down... i.e. actinics, then blues, then halides, then halides off, then blues off, then actinics off.