Gtx 560 ti sli?

Ok i Currently have a gtx 560 ti graphics card
My motherboard supports sli (as rock z68 extreme3 gen3)
I have a corsair gs600 psu (wouldnt use this in sli)
i5 2500k + hyper cooler 212+ (overclocked to 4.4 ghz)
4gb of ram
500gb hdd
120gb ssd
also i game at either 1400x1050 (weird resolution) or 1920x1080 (depending if i use my monitor or hd tv)
I can buy a Gtx 560 ti for $180 or $150 ($200 is budget right now for upgrading)
and once i sell my old asus mobo and amd phenom II
ill be able to afford a good enough psu for sli

The question is that should i not go for sli and go for an AMD 7000 series
or gtx 600 series (when more come out)

Also if i buy a single faster graphics card i can sell my gtx 560 ti (I can wait till the card comes and my computer will still work because of intel hd 3000)and asus mobo/phenom ii processor toward getting a better card that would bring my budget to around the 550 dollar range
but would i need a new psu if i bought a 500 dollar graphics card?
or should i not even upgrade my graphics card and go for ram or get an ivy bridge processor

you could just get a gtx480 for around $200 and it would be about as fast as the gtx560 sli setup but not need to mess with your psu. for some reason newegg raised there price on there 480's after the 680 came out so i would just check amazon for one if interested.

no i wouldnt want to get older tech
it gets hotter and consumes more energy
and i dont think the 480 would match the 560 tis in sli
seeing that 560 tis in sli beats or equals a gtx 580
and besides if i sell everything i could buy a gtx 680 wouldnt that be the best choice?
and i wouldnt need to buy a new psu

Using any nvidia x60 (460, 560, etc.) cards in SLI is a great idea. The performance you get for the value is outstanding. As long as your PSU can handle it I would go SLI. The question is what games do you play at those resolutions? DO you really need the performance?

yeah i know its good
but isnt having a single fast card like the 680 more reliable
since all games dont support sli and it is less power hungry?
and yeah I play games like Crysis - Crysis 2, bf3, skyrim, mass effect 3 and cough call of duty
and yeah performance is necessary in bf3 and crysis (have you guys seen the crysis 3 trailer)
and i record
also if i get a faster single gpu should i get a lower gpu then the 680 or 7970 like the 7870 or 7950 or the gtx 660ti or 670 instead and use the money i save to buy like for example more ram since i only have 4gb of ram and like to dabble into after effects editing and such?
I would like to try the newer tech graphics card thats why (mainly for power consumption reasons)