I don't know, there seems to be a HUGE amount of opinion when it comes to "who is better". It all depends on what you want the computer to do.
If this is just a machine for word processing, web surfing and other light to medium duty tasks, a budget Celeron will do you just fine. Yes, a celeron is just a crippled p4 with half the cache, but you get intel stability at a relatively low cost. Yes I said INTEL STABILITY. (that's my opinion, but I also run an AMD).
If your building a gaming rig, your going to want to go AMD. They just seem better for gaming. I have no data to back this up, but thats my feeling. Plus you are going to need the extra cash you saved to buy all the other top-shelf items you're going to buy.
If your building a system critical machine, you know for record keeping, data storage, number crunching, etc. A P4 would likely be suited better to that task. Again, I have no data, these are just the grumblings I hear.
Since I predict youre going to go with AMD, learn about them first and what you are going to buy. anandtech.com is a good site for reviews on this stuff. Don't bother with 64-bit stuff yet. Too expensive for hardware that has no real mainstream software support yet. Windows Longhorn is slated for 2006 release, unless you like running a beta OS...
Definatly go with a barton-cored version, any of the higher numbered ones are good. I am considering a 3200+XP (
http://www.monarchcomputer.com/Merch...ory_Code=amdxp ), which very closely is said to out perform a p4 3.2 Ghz.
Keep in mind that the numbers that AMD throw on there processor packaging are NOT clock speed numbers. They are pulling a Cyrix trick on this, their reason being that raw speed isn't everything. You can read about this on AMD's site, and many other sites (use Google). The numbers they use are based off of one of their early athlon thunderbird procs, (which also happen to be very close in percentage to the raw speed of p4's..wink..wink)
well at least thats what I know and think...do your research.