Built my kids their own PCs for Christmas (well, bought parts and made them help). Specs are as follows (prices included)
~$340 kids' PC PC ONLY NO PERIPHERALS OR OS
(Some prices were Sale Prices)
CPU: AMD A8-3850 ($95)
Mobo: MSI A55M-P33 ($45)
Case: CoolerMaster Elite 311 Case ($40)
PSU: CoolerMaster Elite 460 PSU ($30)
RAM: Kingston HyperX Blue DDR3 1600 8GB(2x4) ($40)
HDD: WD Caviar Blue 500GB SATA III ($70)
Optical: Asus DRW-24B1ST DVD-RW OEM ($17)
The kids play TOR with me and the wife no problem on the Mid preset, I'm wondering if, at tihs point in time, it's worth getting them a discrete GPU and Crossfiring them. I know it would be an improvement, but would it be ~$70 WORTH of improvements?
You would be able to turn up the detail in TOR for sure, but whether this is a worthwile upgrade will be a judgement call by you. If you proceed, look with a GPU with GDDR5. No reason to stick with DDR3 for the same costs. This puts you with an HD 6670 at a minimum... http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Past that, maybe disable the onboard GPU and go strictly with only a discrete card. The HD 6850, for example, doesn't cost all that much more than the HD 6670 and would offer similar / better performance than the crossfire setup above. There are also benefits of less heat production (with the onboard GPU disabled).
There are a lot of HD 6000 series GPUs for sale on the used market.