an SSD would help with booting into windows and launching applications. as far as rendering video and editing there really is a need to a separate disk for that; it is not a good idea to have the OS disc and "scratch disc to be the same one; it will cause a bottleneck.
here is a list of parts i put together earlier for someone else:
Intel Core i7-3770 $319.99
ASRock H77 Pro4/MVP $119.99
CORSAIR XMS 16GB (2 x 8GB) $109.99
Zotac (ZT-50301-10M) GeForce GTX 560 Ti 1GB Sale Price $ 134.88
get that NOW - such an excellent price!
Corsair Carbide Series 300R $74.99
SeaSonic S12II 620 Bronze 620W $85.99
for the OS:
Mushkin Enhanced Callisto Deluxe $94.99
a scratch disc:
Western Digital Caviar Black 500 GB $ 89.99
storage:
Seagate Barracuda Green (ST2000DL003) 2TB $ 99.88
Microsoft Windows 7 Home Premium 64BIT $99.99
$1160.68 with $44.86 shipping costs TOTAL
$1205.54
now that is a very "high end" video editing build. there are few items that can be downgraded such as swapping out the i7 for an i5. (an i7 is really great for editing becuse the software makes use of the hyper threading)
Intel Core i5 3450 $189.99
that asrock board is really great but that can get swapped out with:
ASRock B75 PRO3 $79.99
a nVidia card is desirable because video editing software makes use of the cuda cores and provides a large increase in speed when rendering. unfortunately that great price won't be available since its a candian web site i had to use for this build
EVGA 01G-P3-1556-KR GeForce GTX 550 Ti $124.99
$109.99 after mail-in rebate card
the case is more because of the budget than functionality that can go down a bit
GIGABYTE GZ-F3HEB Black SECC Steel $19.99
now that is a very sparse case and it doesn't have front UBS3 port but that won't hurt anything.
the PSU is really nothing to skip on, if that goes so does the whole system; maybe permanently if it takes out anything when it goes down.it could go down a little in wattage.
Antec NEO ECO 520C 520W $59.99
unfortunately i have to go and sorry to leave. i can get on what changes can be made to the disks set up, the scratch disk can go and the larger one (media) can get replaced. hopefully this can get down toward $850 before its over.