Considering a shuttle

Greetings from Europe!

I've been on the lookout for a new pc for gaming and streaming HD-movies and the like and I really would like it small sized. I have no problems in building the thing myself or buying a ready made box from a store, but I'd like to have some say in the price and the components of it so I'll probably end up building it myself.

I like gaming but I dont think I'll be needing any over the top-ish components. The budget is going to be around 700-1200€.

I know there's Shuttle as a manufacturer of smallform computers and I've been considering the SH55J2 Barebone (Can't post a link the proper page, damn their url...). If I were to order it, I'll propably have the following components but I dont know if the 300w psu can handle it all...

Core i5 660 (2x3.33GHz) Intel CPU
4 GB DDR3-1333 (2x2048 MB)
SATA 500GB Hard Disk Drive
ATI Radeon HD 5770 1024MB

For a whopping grand total of €931.00 (Not including the display, going to buy something other than the one shuttle sells or a BlueRay-drive (as shuttle doesn't offer any for this barebone...)).

Are there any other manufacturers I should see to or am I better off (price-wise) by buying the components and the case and building it by myself? I will likely end up with components along that line if I build it myself: Two cored i5, 4GB of memory and a Graphics card like that one.

I've been out of the component-business for awhile now so I haven't cooked up any proper alternative for the Shuttle-build, so any help with that is most appriciated.