I recently got the TSC ASW-8 to go with my M-Audio AV 40's, and I've got to say that I'm thoroughly satisfied. It plays crisp and the response is tight. The 8-inch version suits my 10'x10' room fine, but if you're in need of more bass there's also a 10-inch version.
It's a downfiring...
I recently got the AV 40s and an 8" sub to replace my damaged Logitech Z-2300 system. The sound is 10x better, but one thing I could use is a way to control my sub's volume levels. With the Z-2300, both the volume and bass levels were conveniently placed on the same control (pictured below)...