I prefer to avoid compression at all costs-I figure any that's added during mastering is enough. Of course that's my personal preference. I know that there are some sensational compressors out there, but the most transparent one to my ears is no compressor at all.
Absolutely no compression on kicks. Vocals sometimes with a very dynamic vocalist. But I prefer no compression on vocals. It used to be a lot more work in the old days because we used to do fader rides to even out the levels. This would take about 3 to 5 hours. Today with Logic I can do it by myself in less than 30 minutes. It's really easy with Logic automation because I can see the waveforms and just pull drag the levels up.
not to sound like a know it all (it is up to you if you use compression), but I think it is a neccessary part of the production process. compressors smooth out your sounds! they allow you to hear the full sound (ie the low amplitude "tails" or quieter sections that you might not normally hear are brought out). I definitely notice a much fatter sound if I use compressors (and I use them on most things.) just my 2 cents though...