Oracle Server Question

Hey group,

It's come time to quote on a server for our Oracle project that's upcoming. It contains a very large amount of data, with many hundreds of transactions per day, and we need to access data from about 2 years back at any time. We do not plan to integrate with the web any time soon, and will only have 2 (very rarely 3, and almost never 4) people interacting with the database at one time. The plan is to run it on Solaris, it being a stable environment. Any suggestions as to which server(s) I should look at? Should I go with one from Sun, or Compaq, HP, etc? Any tips when looking for servers?

Thanks In Advance