So you just bought and assembled a brand-new AMD64 workstation. The only decision that remains is whether to install a 64-bit Linux distribution, or stick with comfortable, tried-and-true IA-32. If you are seeking an easy answer to that question, I can't help you. Running 64-bit Linux has its pros and cons. Unfortunately, a lot of the cons are out of your hands -- but they're not really Linux's fault, either.
Read the full thing at http://www.linux.com/article.pl?sid=06/09/07/1632253