cheep gaming system for my sister:

GIGABYTE GA-M68MT-D3 AM3 NVIDIA GeForce 7025/nForce 630a chipset Micro ATX AMD Motherboard
$49.99

AMD Athlon II X2 250 Regor 3.0GHz Socket AM3 65W Dual-Core Desktop Processor ADX250OCGMBOX
$63.99

CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model TW3X4G1333C9A G
$36.99 AR

Already purchased:
Antec TruePower 550w power supply
$39.99 AR

Lite-On DVD-RW
$15.99

My spare parts that'll be used:
Sapphire Vapor-X Radeon HD4890
mATX case

I'm debating between having her buy a HD, or upgrade to SSD and give her one of mine..I have enough space that it won't kill me to lose 1Tb.

She has $100-120 to work with right now so I'm helping out a bit..budget is (obviously) not too high, hence the X2 instead of a quad.

My first thought was to see if there was a cheap Phenom II X2 which you might get lucky and unlock to a quad, but unfortunately they are significantly more than all the Athlon II X2's. Gonna overclock?

I do find this odd - you picked the: AMD Athlon II X2 250 Regor 3.0GHz

but

I noticed the AMD Athlon II X2 255 Regor 3.1GHz is actually cheaper at $62.99 FS

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103896

Unless you find a 15x multiplier more desirable than 15.5x might as well get the extra 100mhz for cheaper.

My only other thought is have you tried fitting the 4890 into the mATX case? I remember when I tried putting a GTX260 into a mATX case I had to cut into the bottom drive cage to make room.

oops, picked the wrong one..I did notice that earlier. Nice catch..thanks!

I haven't yet test-fitted the card in the case - that's on my list of things to do.

There's actually a really good deal running at Microcenter now...a 250 with a board for 58 bucks. I'm trying to find someone to get one for me. I may just drive down (~2 hours) sometime this week..

I think I read somewhere that the later NVIDIA chipsets had a bad reputation for dying young. You also can't unlock CPUs from dual to tri/quad core with them, though with your choice of processor that won't matter. The AMD 770 chipset (with, I think, the 710 or 750(?) southbridge) and above would, but yeah this is becoming less and less relevant.

I had an nForce 430 last me 4 years, 5 months of which of was spent outside in a bin. I always hated the BIOS though, not enough options and no overclocking.

I would risk it. Gigabyte GA-M68MT-D3 has a 3 years limited Manufacturer Warranty for Parts/Labor on motherboards. It's only a $50 motherboard anyway.