Looking for Pre-amp suggestions????

Here is my issue/question???

I will be mounting a 42 inch plasma on a wall in a living room which will be flanked by a pair of Magnepan MMGW's and an Earthquake subwofer. I am using an acurus A150 to power them with a Rotel RDV1040 DVD player. I am looking for suggestions on what pre's offer digital inputs as I want to run the Rotel via an optical or digital coax cable. In addition a subwoofer output would be nice. I am open to any brand suggestions if they meet the above criteria and don't get crazy on the price to performance ratio of the above equipment. Would like to keep the purchase under $500.

Any thoughts?