FF14 specs havent been released yet, so you cant choose a card based on that.
PCI-E is good, as is 750 Watt.
ATI and Nvidia are the ONLY 2 companies that make the GPU boards, they then sell the boards to the likes of PNY, ZOTAC, GAINWARD etc and they stick there own coolers and overclock the RAM and core of the GPU
So its down to your personal choice, as for deciding on a card the main factor when buying a card is the resolution of the monitor you plan on using it on, no point buying a powerhouse if your playing on a 15" monitor :D
so come back with the res etc and we can go from there...hope this helps
8600GT - whats wrong with it?