It's definitely SQL Server. It seems like SQL is caching the table data in RAM but never freeing up the memory again. I haven't found anythng related to my problem at MS but am still looking.
Do you know of anyway to adjust the amount of time SQL Server holds data in RAM before flushing it out to the disk and freeing up the memory? I've had a few more knowledgable database people tell me that SQL NEVER gives up the memory and that every SQL server needs to be rebooted periodically - is this true?

Thanks.