Are we talkin about something like those shuttle pc's, one problem with those shuttle things, if for some strange reason god descides to stop the one and only fan on that thing you could probaly say good buy to your AMD, seen as i have only seen AMD powerd ones then yeah, Not everything is intergrated, it does have a AGP slot, as far as i can see though. Umm another thing is if for instance you wish to upgrade you memory this is the sequence you would experince.
1. Take cover off
2. Take out Power supply / CPU fansink
3. Take out CD-ROM drive and HDD (on same bracket i think)
4. Take out Stiffy Drive
5. Admire the "Cuteness" of this what they call a PC in front of you
6. Put in memory
7. Put back together
So then 2 Hours, 3 cups of coffee and your mothers intire cookie jar later you have upgraded from 256 to 512
So ye me myself and I prefer the good old ATX Boards and cases.
Maximus.
PS: this is from what ive seen of these things. if im wrong please correct me.