I just bought something interesting from Guitar Center. I went there to buy a Auralex Lenrd bass trap for a trouble corner of my room behind my left channel. They had these Auralex Gramma's, which are used by bass players to put their amps on for decoupling purposes. I bought two of them to put my floorstanding speakers on, and it's made a huge difference. Even though my speakers are (were) on spikes and small brass discs, they were too bassy to leave my port bungs out. I removed the spikes and put the speaker directly on these things. I'm finding that they now sound like they did with the ports plugs in. They're not too pretty, and when my wife gets home from work today she's going to probably start crying, but they're very effective for decoupling your speakers, especially on hardwoods. I can now listen to Cassandra Wilson without a horrible low frequency reverb type of sound.
I put the spikes back on. Made a huge difference with the Gramma's. I feel no vibration in the floor at all, whereas with the spikes on discs on floor produced a decent amount of vibration from the floor. Bass trap seems to work as well.

Someone on Agon said they cover their TV with a blanket. That makes a difference in my room.
I put a sub on one of those, what a great, cheap improvement.

Excellent string to share this info.