ATX vs Micro ATX

Hi. A mate is building a new pc and originally wanted the ASUS P5W DH Deluxe SKT 775 dual-core mobo http://www.ebuyer.com/customer/products/index.html?rb=23208426185&action=c2hvd19wcm9kdWN0X3NwZWNpZmljYXRpb25z&product_uid=113951
but thinking that it was overkill for his needs is now thinking of the ASUS P5V-VM DH
http://www.ebuyer.com/customer/products/index.html?rb=23208426035&action=c2hvd19wcm9kdWN0X3NwZWNpZmljYXRpb25z&product_uid=113956

the latter is a micro atx. will it fit in the same full atx case? he is going with a core2duo E6400 so is the second board worth going for? what do the different chipsets really mean?
sytem spec is OCZ PC2-6400 2gb, 2x Western Digital WD2500KS Caviar SE 250GB, Asus Nvidia GeForce 7600GS Silent 512mb DDR PCI-E, BenQ FP91G+ 19 in TFT. Only going to use the pc for mp3s, dvd, and photo editing with photoshop. I thought the asus p5w dh mobo was extravegant for his needs.
all comments welcome.
mant thanks.

micro/ultra atx should fit in an atx case. Main difference is you loose a couple of pci slots and theres a slightly different layout with the ultra-atx format.