No hard and fast rules here.... I tend to EQ first and ask questions later.
But sometimes it's advantageous to tame the dynamics first and then refine with a little EQ after. They tend to produce quite different end results (well, for me anyway).... if you're asking the question on a particular track, try both routes and compare the results
It is important to think about how one processor will effect the next one in the chain though
eg. if you boost at 80 hz with eq and then follow it with compression the compressor is having to work harder in order to tame the high energy peak at 80 hz.
This will affect the way the compressor sounds and how well it performs its duties in this instance.
So for more transparent compression and effective dynamic control you may choose to compress first then eq afterwords in this situation.
EQ before compression probably 90% of the time. On the SSL if you use the dynamics section on channel input, the gating is also pre EQ, so I tend to always use channel out mode, so that the compressor/gate is post EQ. This gives the sound a more punchy in your face quality, and allows you to use the compression/gating to control transients/noise caused by aggressive EQ boosts. However there are times when you want the compressor to function as smoothly, and sound as natural as possible. In that instance I filter/cut pre compression, and apply any EQ boosts post.
And whatever way that you do it....what would be the circumstances that would have you to do it the opposite way? And explain.
I usually eq before compression too, but because of the character/sound of different compressors, i usually use a 2nd EQ after to make sure it's still sitting right with the music!