You should look at the Antec SX1030 or SX1080. They are full tower cases, which should be what you really ought to go for. Aopen has a case, the HX08, or HX04 (can't remember), that's supposed to be really good for modding.
I just picked up a dual P3 board and it is HUGE! 12.5x10.5 inches, my midtower I have is fairly cramped with it. Plus the drives that stick out are in the way of the DIMM banks, but there is enough space there that I could install another DIMM. It's just that the drive has to be manuvered around.
Firstly, a dual board is going to be rather large, so make sure you have plenty of space. Second, look for something sturdy. I used to have an Aopen case that while heavy was a solid as a rock, so I would definitely look at Aopen.
With a full tower, you have more to mod, as well as enough space.
Do know that the Antec case will run you a little over $100, but from what I've read it's a very good case. It comes with 2 fans, and the fan in the 300W PSU adjusts its speed according to the temp.
 
I don't have either one, because the full tower I got was cheap, but sturdy enough for me. However, I've never seen a case quite like that Aopen.
 
In short, look at Aopen or Antec.

Check out the Coldforge AA-15 It should be available very soon!

thanx for the responses the aopen looks pretty good as well as the cold forge when its done.the aopen will probably be the one i get.just out of curiosity anyone know where alienware get their cases from i would'nt mind one with a hydralic front on it, i could think of some pretty cool stuff to do with that:D

ok i changed my mind im now also considering the antec case i saw one a fry's and was impressed by it almost forgot about that one, i really liked the slide out cages in it because im always changing out drives and such thta would make it so much easier. again thanx
Quote:musoan "dream for the future"

I've got a GlobalWin 802 mid tower case, and it's great. However, I've just bought a Lian Li PC70 aluminium full tower case. It's fantastic.
 
I've got a review of the case on my site if you're interested: www.philspcmods.com/reviews/llpc70

SuperMicro SC760A does me just fine. Lots of room inside for HDs, fans, you name it its got it.
 
--Cynan.

http://www.servercase.com/ImageFiles/SC01F.html
http://www.apextechusa.com/atx_tower_case.html
 
Look at the ATX 100FT version I own one so I recommend it.
Heres a review:
 
http://arstechnica.com/reviews/4q99/supercase/apex-atxft-1.html
 
I suggest you buy a better PSU like a 400watt. Besides that it handles fine. Plenty of airflow.

if your looking for Dual Athlons I recommend waiting until the Athlon 4 workstation chips come out and get some of those.

I have that AOPEN case and its fantastic.
Absolutly huge
6/7 hard drive bays (3 of em are below 5.25, other 4 are ontop of ps)
3 vent holes for 80mm fans
5 5.25 bays
a removalbe top that I will shortly be cutting 2 holes in for "blowholes"
The only bad thing about the case are the sides. THey have to slide of all the way, thus making it impossible to mount a fan to it, but..there is one opening at bottom front and 2 openings just above ps for fans.
 
I am really happy with it, its on the heavy side though
30+lbs!!!

wow i never thought i'd get so many responses, thanx to everyone who responded,but after much consideration and research, i have decided to go with the lian li pc 70,it's aluminum so it dissapates heat faster and its lighter than regular cases,plus it has room for everything i'll stuff in it,plus it has room for 5 fans before i mod the hell out of it:D well maybe not that much. but thanx again.

ye thats a sweet case...but lotsa $$$

The PC70 will actually take 6 fans in total. It's fitted with two intake and two exhaust fans already, but another 2 x 80mm fans will fit in the PSU bay.