If 3.4s and 3000+'s are the same price nowadays, then overall I say your best bet is to go with AMD. Later on you'll be able to throw a faster CPU inside the socket 939 should you want to.
I have a 3000+ currently and it gets the job done great. Gaming will benefit with the AMD64.
In the end it's up to you, but I think the AMD route offers a little more breathing room for the future (CPU upgrade, 64bit software, etc). Just make sure you've got 1gig of DDR400 to go with it and it will really shine.