Yes, a common thing with CRT's, if you have a CRT use www.blackle.com instead of Google.
However, it doesn't work for TFTs, some of them even use more power to display black.
As far as light bulbs are concerned, don't use LED's, they're rubbish, the light quality is terrible and the lamp life is seriously not as good as stated (maybe on average, but not in practice, of the two halogen replacement LEDs we have 3 of the 9 bulbs in the arrays blew after a month).
The main culprit is halogens for us - we have 10 in our kitchen, 10 x 50 watts. Ouch. We've replaced tham with flourescents, they are the same size as halogen bulbs, but draw 7 watts. They are a bit expensive and be warned they are too deep for some fittings, but just in our kitchen they save us £100 a year. UK site www.eco-lights.co.uk
Another top tip - we've found with bayonet fitted flourescent bulbs that Tescos own brand actually fire up quicker than the more expensive brands.... It's worth buying a few different types because the difference in start up times is quite marked between them.