I won't answer you about what monitors to buy, I am no expert and the prices will be totally different in europe than here. Just make sure, for EyeFinity, they are all the same size and resolution. Having a larger middle monitor (size wise) then the outer monitors would look very weird. Having different resolutions is not supported yet either. Also, if possible, make usre one of your monitors has a Displayport input if possible, that will save the expense of having to buy an active DP to DVI adaptor (109 euro from
here for example)
As for the card, if you can afford it go for the most powerful version. Running 3x1920x1200 is a lot of work (6.9 MegaPixels! A 30" screen is only 4!!) so a powerful card will be required for a lot of games. Myself I am holding out for the x2 and/or 2GB version. having run 3 monitors for a while I know you need the best card/s posible if you want high FPS and AA/AF.
As to the rig, I am not going to upgrade my q9650, there is no real reason. Gaming at such high resolutions is totally GPU bound, not CPU. A 750 as you suggested would be perfectly fine (if I find that I need to upgrade to get a CrossFire mobo I will be using the same CPUas you suggested)
Welcome to WSGF and enjoy the pure awesome that is :triplewide
:)