Also used now on Audiogon is a Vansevers Model 83 and Model 85 for a little over $300. I would start with the 85 as my first choice because it has more digital plugs than the 83. The 85 has two separate pairs (4), so for digital you can keep the TV and DVD on separately filtered plugs for better issolation and filtering. The Vansevers list for around $600 new and are a great value for the asking used prices.
I would personally skip the Monster conditioners which I am sure will get recommended. They work OK if your budget was only $150 or less, but are over-rated above that in my opinion.