I highly recommend not compressing the track overall. I've heard people state this on some other boards, but compression has brought us to the land of "whet the hell are dynamics (variances in musical volume)?" If you over compress, you get no dynamics. I get all the umph I need from minimal use of compression where I want it in the track. Sad thing about compressing in live is that there is no side chaining (yet - fingers crossing and all). Now, all this depends on the style of music that you're making IMHO. If you're making bangin' arse Trance or hard house, go ahead and max out the compression. But if it's something more subtle, you might want to use compression more sparingly as I do on your drums and your bass lines to make sure that they don't muddy up. If you need to make something stand out more that is too quiet in the mix, try saturation - it works well for me.

I'm not savvy on any plug in compression right now. Sorry if I'm more spouting my opinion than helping, but this is an issue that I take to heart. I miss dynamics.

Don't use compression on the Master output. Use A limiter if anything. If you want a sort of magical ARS style limiting then I highly recommend either the PSP Vintage Warmer, Waves L-2 Ultramaximizer, Wavearts Final Plug (much cheaper than waves as well), or Izotope's Ozone.
Overall PSP vintage warmer is probably my favorite.

Don't want to imply that this is my specialty but...I like using just a little compression. If you want to go analog, the Keelly pedal just KILLS. Compression is one of those things that is easily over used-not everything in a mix should be even. Maybe go through your track and look to where you want compression to happen and turn it on there...

Also-check out the Waves compressors and play with Aura Exciters-you may need that more than compression-

IMHO-LOL! Just suggestions...