Hey, I won't be serious this time :)
In year 2005 Gabriel Wicke cited 1 year old message:
- Some new web servers(3 or 4), P4 2,8Ghz with 2Go of RAM
The web servers use about 210Mb ram currently (according to 'free'), 512Mb ram and no raid for web servers would buy the same performance for the same money.
You can still all take a look at http://meta.wikimedia.org/wiki/Hardware_report%2C_March-June%2C_2005
One year ago we had slightly different loads ;-)
Cheers, Domas