I've got a Seasonic mATX 380W in mine, but it's stripped now, on-board graphics, just one HDD etc. The PSU has the same dimensions as the original and it's plenty.
The general opionion seems to be that Seasonic PSUs have the power leads coming out on the outboard side of *** 5.25" drive cage, but the full size one still blocks the drive cages to an unacceptable degree in my opinion.
Is it worth the money? No. But then what is? If you want value, buy a Lian-Li and keep it for life.
For a cooler I'm using a Coolermaster Aquagate MiniR120 (don't laugh) with 2 Akasa Ambers for quiet. The RAD is on the outside of the case, with one of the Fans mounted conventionally inside pushing air into the RAD and the other mounted outside, sucking air through the RAD. It's £50+Fans, it's silent and it is better than any of the other cooling solutions I've tried in there (Zalman, Akasa, Arctic Cooling, Swiftech, Silverstone).
I've got a P4EE in there and it runs at 50C flat out 24/7 at a little over 4GHz.
As for the LEDs - AC Ryan do a fan that lets you independently vary the speed and the LED brightness. They worked quite well as I could turn off the lights at night.
Overall - I've had shedloads of fun with it. I've built loads for other people too and they're all very happy with them. The Shuttle is much better if you don't want to play with it, but if you're a modder/tinkerer, buy the Aspire.
Below are some pictures of my rig as it was back in October of last year with the same cooling but Akasa 120mm Blue LED Fans.
http://www.walteranderson.com/100_0530.JPG
http://www.walteranderson.com/100_0531.JPG
http://www.walteranderson.com/100_0532.JPG
http://www.walteranderson.com/100_0533.JPG
http://www.walteranderson.com/100_0534.JPG