I just got my BX5a Deluxes and absolutely love them, but I do notice that the base has a dramatic falloff in the deep range, so I'm now looking for a sub to pair with them. Obviously the M-Audio SBX10 is ideal, but damn is it expensive (3x what I paid for the speakers.) Is there any decently...

I know this seems like a topic that's been run through a ton of times, but after a lot of Googling I can't find a satisfying answer. I'm looking to get some nice speakers for Christmas to go with an X-Fi HD (the USB version, since I have a laptop.) Since the BX5 D2s came out, the price on the...