I feel exactly the opposite. Back in the old Athlon XP days when you were comparing to the first-generation Pentium 4's that may have been true (office productivity = intel, games = AMD) but that hasn't been true for at least a year and a half. Not counting the brand-new and barely-available Core Duo, nothing Intel has out right now can hold a candle to even the low-end Athlons.
Plus, if you are concerned about upgradability at all, then the AMDs are definitely the way to go. Intel changes chipset requirements for just about every new processor that comes out, which means that you'll need a new motherboard (and sometimes new RAM) in addition to that shiny new processor.
Right now I have a $150 Athlon64 3200+ which performs at least as well as a $180 2.8GHz/800MHz Prescott. However, with absolute ease, I overclocked my little 3200+ from it's stock speed of 2.0GHz to 2.5GHz (I was being conservative, I could have fiddled with it and probably gotten 2.6-2.7), which is roughly the speed of their high-end Athlon 64 FX-55 processor ($811.00). Once you overclock them, nothing can touch them for the money. The beauty of it is that I'm still using the same video card and same ram as I was when I had a Athlon XP 1.2GHz processor. If I want to drop some cash and throw a dual-core X2 4800+ I can do it, with my existing board, ram, video card, etc. Try doing that with an Intel board...
Check the benchmarks and
this pricing guide for more information (and
here is a huge list of reviews of AMD's new FX-60 which usually include older processor benches too). Make sure when you're looking at the benchmarks you compare pricing too. When a $800 processor you can never afford barely ties a $300 one you can, then which one really wins?
The one thing I do agree with Gamer on is that if you aren't building it yourself (why wouldn't you?) there are more options with Intel. That's not going to last though. Honestly, if I were going to get an Intel system (which obviously I wouldn't), I would certainly wait for the
new Core Duo systems to show up in force. Finally they're abandoning the
Netbust Netburst architecture and are beginning to be competitive again.