If you for example EQ in a bass boost and have it before the compressor, playing low notes will make the compressor clamp down more than it otherwise would, so the comp is fighting your EQ changes, therefore you might want the EQ after the compressor.
On the other hand, say you're a heavy fingerstyle player and are using the EQ to get rid of clank - you might then want the compressor after the EQ, no point feeding the compressor frequencies it's going to react to when you are just going to cut them afterwards.
So, it depends!