Do you plan to have a PC that you shall be constantly upgrading with everything possible? ATX gives you more upgrading possibilities with cards and stuff, barebones wouldnt.

Also if you go for a top o' the range card the heatsink can take up the PCI card slot aswell, so you wont ever be able to add in more cards then.

With a barebone like Shuttle you arent as handicaped as most think.

ya wil be forced to use most of the onboard stuff with a shuttle (but that aint that bad).
ya wil be able to put a grafiks card init
and then wil have 1 PCI Slot left.
and power wont be a real issue as they usualy got good PSUs

cause the AGP slot is on the outside of the board and the PCi on the inside the Cooler of the grafix card wont overlap the PCI Slot.

if ya got a grafix card with a dual slot cooler ya can get problems cause it wil stick out but for this stuff there r small mods.
.

but on the upgrading part ya r handicapped with a barebone.
the mobo and case r 1 piece so when ya wanna switch from intel to AMD or vice versa or another socket ya wil have to buy a whole new thing.
but for lanning they r the bomb.
another con is that barebones can be pretty loud.


if ya got money enough ya could get a cheap barebone for lanning and a normal ATX for home.
as a ATX case maybe one wich can be converted to BTX (if that new format ever actualy gets out) cases that can do BTX r the new Lian Li (big price tag) or the new coolermaster Stacker (nice 120mm fans)


if ya wana read alot of stuff about barebones i advise looking at this forum:
http://forums.sudhian.com/index.cfm?FTVAR_SUBCAT=68&nocookies=y&subcatname=SFF%20TECH
alot of people disscusing about Soltek, MSI, Biostar and Shuttle barebones.
also some cool mods.
(still love the guy that managed to build a complete watercooling set inside of a barebone).