SFF Nightmare... 64bit or 775 PCI-Express?

[Napster]

So my parents agreed to fund my college computing experience.. But i want something with performance that will be smaller than a desktop but more powerful than a laptop..

So I want a Shuttle (See pic.) But it will need to last me.. PCI-Express hasnt shown too many noticeable results... SO what should I do? Go with an AMD 64-bit Shuttle or a 32-bit PCI-Express shuttle??? I already have an intel and would be interested in trying AMD... But if PCI-E explodes into something great I don't wanna be left in the dust....

Please Help