My personal opinion 3 monitor current or near current cards:

For legacy engines simming (FSX, IL COD, Skyrim, rFactor2 etc) : GTX 680 or wait for GTX 685
For general gaming on modern engines (BF3, iRacing, Dirt3 etc): HD7970

One Other option you have is SLI your current card with either another 460 or I've heard it will SLI witn the 560Ti/448 like mine, but my personal experience is SLI and crossfire is hit or miss on whether particular games benefit from it or it causes problems.

Your mileage will vary that is just my own personal opninion.

When choosing a stock higher clocked card for Eyefinity, the 7970 beats the 680 (stock OC) in this review in all games tested including Skyrim, except WoW (11fps diff) and Mass Effect 3 (2fps diff).