Asus boards are great, I did hear of some stability issues with the Abit KT7 board in the past... perhaps they have been resolved...
I run an A7V KT133A, jumper free and not had a problem with it. This board supports both RAID and ultra 100. (plus the manual lists which slots are shared lol+)
TBird would be my choice, as fast as you can afford if clocking is not a concern.
I run an Antek 1030 case, its a good size with lots of bays. It comes with a 300w PS and i believe you can get it in black and I think with higher rated PS. It comes with 2 exhaust fans as well as 2 ports for 2 more intake fans. Probably the best case I've ever bought.
Might as well get as much ram as you can afford. I have no experience with DDR so I won't say anymore +)
I don't think SCSI is really worth the money for a home gaming system. You have a harddrive now.. I dunno how old it is, but do you NEED to buy a new one?
Whenever you buy a motherboard you can usually buy an OEM copy of an OS. WHich is often less than half the price of a boxed OS, and there is NO difference between the retail and OEM version of the OS.
You can install it yourself, its fairly straightforward.
When I install on a blank HDD, once FDisk is complete, partitions set etc, I will copy the OS disk to the harddrive, and then install from there. Its much faster, and you never have to go scrambling for your windows disk when installing some drivers or hardware ever again.
If you have the store install the OS for you, just make sure you get the disk! and the legal stuff.
My thots
SKurj