the Asus P5Q-E would be a good choice, since you don't need the dual x16 PCIe lanes of the x48 chipset. It has most of the features at half the cost.
1) Asus P5Q-E
2) $160 for this mb on newegg
3) it has the most up-to-date features of a pre-nehalem board
4) I can fit my xigmatec hd-1283 on this board with no problems
5) dual monitor support is a function of the graphics card, not the motherboard.
This board has built-in firewire, which is good to have for digital audio production.
This board has an on-board RAID controller that will do raid 0,1,5,10
This board goes up to 1600Mhz FSB
Drivers are a function of the OS
for PSU - try the any of the corsair HX series
OS - you cannot upgrade to 64bit from any 32bit OS, so you should make sure your equipment has 64bit drivers that work properly with Vista 64 if you plan on going that route.