There aren't many sites that have benchmarked using SQL Server. If you can dig up some proof that Xeons can outperform Athlons on this benchmark today, point 'em out. Inquiring minds want to know...
I do want to point out they benchmarked a 2.2GHz Xeon against a Palomino XP 2000+. Bob is considering a 2.4GHz Xeon and MP2400+ are readily available.