I've had some great results using a digital EQ in my system of late because for a long time i've had issues with very poor bass responce. I set the speakers up the best i could at a 1m off the corners and 30cm off the back wall, that possition gave the best overall balance, further away from the back wall and the sound started to get 'thin', closer and the bass started to 'boom', the overall sound still lacking though, basically i needed more cones.
I've lived with the set up for a few years but over time have been putting all my music on a HD and playing it through iTunes. With it i started playing around the iTunes own 10 band EQ which gave me the option of tweaking and it helped with the poor low frequencies in the room though but felt i needed more control.
Now i'm using Apples free AU Labs 31 band EQ with Soundflower which gives me more control. I dont know if its totally transparent but it has transformed the music, just by adding a very small amount of db's (scaled 0 to 2db's) from 50hz down to 20hz has added a solid foundation with bass that goes deep but still stays clean, perfect!
As a bit of fun i've also been able to play around with the EQ to counteract the "energy" i have in the upper mid by flattening the peaks a db or two.