Still trouble deciding

Well i depends how much the gtx260 216 core and the 4870 1gig?
I believe there both well above 250$. A card like this is more then enough:
http://www.newegg.com/Product/Prod [...] 6814127361

In sli 2 gtx260 in sli perform great.

or you SLI 2 9800GTX's for about 300 since you can find them for 150 and below. And they run incredibly cool my single one on 3% fan runs 70C under full load but when at 90% only 40C under full load and still quiet. But my optical is really loud.

First of all, get a stock 4870 1GB, not POWERCOOLER

Not quite...

GTX 260
As stable as any GPU is I suppose
Drivers are working, though the beta drivers for Far Cry 2 are terrible
Looks like a card....
Decent customer service, EVGA to tends take their time but they are good.
Cooler is... average
The core 216 sucks at overclocking and the older version can match the core 216 with some overclocking

4870 (stock)
Very cool (with the fan set to 40-50% the card will idle around 40c and hit 65-70c load, much lower than the GTX 260)
Drivers are perfectly fine, ATI sucks with their 4870/4850 X2 drivers
As long as you don't get POWERCOOLER or don't expect your rebate from Sapphire, the customer support is generally good.
...burn out? Umm, well the card is built to withstand high temperatures so when it is subjcted to great temps (40c/70c) it will most likely last a long time...
Overclocks well thanks to good temps, but nothing legendary like the 8800 GTS 512

In the end the 4870 1GB is slightly faster, though you wont really see the difference. The DX 10.1 the 4870 offers is useful in Far Cry 2 and does make a difference, but whether or not more games will adopt DX 10.1, I don't know. If you want to double up your cards later then the 4870 is a great choice since you do not have an SLI/crossfire motherboard yet and an X38/X48 motherboard is very stable and overclocks very well, while nVidia motherboards are... terrible.