Finally decided to upgrade my Graphics, still running my old 8600 GT, so im a little behind the times, Was wondering which graphics card i should get, sicne Im not very familiar with current graphic cards, Plus, being that the 550 Ti's are so new I havent heard much about them. Would love to have a few good answers since I am buying 1 of these guys next week. Thanks =)
A single GTX 580 is a better option, if you can afford the extra cost.
It will generally outperform a pair of GTX 550 Ti's and, as it is a single GPU solution, its performance will be more consistent by not being reliant on SLI profiles.
If you could post the rest of your system specs, including information regarding your PSU, screen resolution and budget, we could better advise you on your upgrade options.
It may turn out that your needs would be best satisfied with a somewhat slower GPU and an upgrade to other components.