Server Specification Enquiry

Hi,

I am a DBA in a concern based in India having a Database of size around 200 GB.

We are in the process of getting a new Server for a new module of ours.

Our Database size on the server would be around 20 GB in the Initial stage, which would grow at the rate of 250-300 MB per month. There would be 400 concurrent users acessing the database which would include Insertion,updation with very little or no deletion processes.
The database is Oracle 8i on the Windows 2000 Server platform. We are projecting the usage of the hardware for the next 2 years.

Any help on the hardware specification for the new Server would be greatly appericiated.
Any further details or clarification would be provided instantly.

Regards,
Manish