I don't have any experience with a standalone digital equalizer (last time I used any EQ was like 15 years ago). But among affordable EQs, I hear many good things about the Behringer units. Especially, the new DEQ2496
seems darn good, at the street price of ~$300. It has a built-in RTA (spectrum analyzer), which enables fully automatic room equalization. It seems that EnjoyTheMusic.com plans to do a review article on DEQ2496 soon.
For subwoofer EQ (to bash room-mode peaks), the Behringer DSP1124P
seems to be a popular choice (street price ~$120).
The only caveat on these "pro" audio gears is that they are configured with XLR balanced inputs/outputs, operating at line signal levels that are higher than the home audio standards. People seem to prefer using these gears with digital in/digital out.