We've found that specifying the hardware correctly is of far less importance than carefully tuning queries and using ADO's ability to reduce round trips by grabbing multiple recordsets at once.

You've worded your requirements quite generally. If you're going to grow at 200MB per month forever, you'll never have enough RAM to keep the whole DB in memory. So don't even try. Just use good programming techniques such as proper use of indexes, well written queries; and a fast fat disk system. And until you can adequately judge the number of concurrent users, you have no idea what your basic hardware requirements are.

Student of SQL and Golf, Master of Neither