Recommendations for a small subwoofer?

[ffutures]

I'm thinking of getting a small powered subwoofer for my home cinema setup, which is in a room about 10' x 15' with a lot of sound absorbent books, sofas, etc.. Doesn't need to be hugely powerful, I'm just looking for a little more clarity on low frequency sounds. Really DON'T want to shake the house and annoy the neighbours!

Any recommendations?