I use Eq all the time, almost always for cutting resonant/peaky frequencies. I've got some Nebula Eqs which are supposed to be very good emulations of real hardware Eq units, but I rarely use them (just subtle usage in the mastering stage. There's a lot of talk about how 'good' or 'bad' software eqs are. I have to say, I'm just not totally convinced either way.
For me, a good 'working' eq is low cpu (as I use lots of instances in every track I'm working on) and has a spectral display. I'm mostly just using high pass and low pass roll offs for synth sounds with a 'full' spectrum. I use the 'peq2' eq that is part of FLStudio, it fulfills the above criteria. I'm sure it could be argued that it may not be the last word in quality, but it's very easy to use and for ''corrective' eq-ing, it does the job.
APK's suggestion looks a good one for a vst solution, mine perhaps less so, as 'peq2' is part of a DAW.