web server? for 2000 student college

[John Gresham]

We are getting ready to purchaser new web server for our university of 2000 students -- this would host all university department pages as well as some student organizations and university outreach programs such as summer conferences etc.  Also, we have a small but growing use of the web for courses including both faculty and student pages that we would host.  (possibly on a second server) We are
beginning to use some multimedia (realaudio etc) applications on the campus and I have had requests for chat services so there are possibilities for developing new applications -- I would be interested in hearing what similar size institutions are using and also ideas on quantifying storage/memory requirements for web servers -- how do you know how much memory/storage you need?
thanks as always,
john gresham
francisan university of steubenville, ohio