Here in CA:
We used 34 watt T-12 lamps on commercial work for quite a while, to comply with our energy saving Code (Title 24)
Any new work, we use electronic ballasts with T-8 lamps (and now, T-5 is the up & coming thing).
BTW, the number assigned to a lamp is a reference to its diameter.
1/8"=1, therefore T12=1-1/2", a T-8=1", T-5=5/8", etc.
CW is only the color of the bulb...Cool White, which is generally 41K, is an intermediate color.
"Daylight" lamps, @ 50-51K, might look "blue", but are actually close to daylight.
There are lamps made @ 27K, to soothe the eye of those that are used to "soft white".
[This message has been edited by electure (edited 12-30-2003).]