GTX660 Ti

Might want to consider a 7950 for a similar price if you are looking into overclocking your video card. I personally own a msi 660ti oc edition and i've had almost no issues aside from initial driver install. You wont have issues playing any game at that resolution though, at 1080 you'll notice some games like bf3 and skyrim will have dips but never below 40fps.

for the time being will keep at 1600x900. maybe it will be a few years before i made an upgrade to new monitor. btw 7950 (reference clock) cost way more expensive than GTX670 from where i got my stuffs. i know radeon cards are having price cut but here where i live it seems the price doesn't change much. last time i checked 7870 have the same price as GTX660 Ti which is around USD350.

As srftwhm said, a GTX 660ti will run games just fine up to 1080p (1920x1080) so at that resolution, it shouldn't have any problems at all. If anything, you could even overclock your CPU a bit given that it's a K model, just make sure that your thermals stay within reasonable boundaries.

The problem with price cutting, is that most retailers bought the cards at original price, so they can't readily pass on the price cut. Between a GTX 660ti and an HD 7870, I'd go with the GTX 660ti for your monitor. Just my 2 cents.

Also forgot to mention that if your planning on borderlands 2 it comes with the 660ti at the moment. Also the 7950 comes with sleeping dogs so both have pretty good deals going on right now.

660ti also comes with a 192 bit bus where 7xxx comes with 256 bit

Only noticeable if you go past 1080 resolution or multi monitor gaming, at the resolution he's at he wouldn't have an issue

I thought high levels of AA and some settings needed bigger bus as well?

That is a great pairing with a lower resolution monitor the GTX 660 Ti quite readily outperforms a 7950 even with AA settings cranked up.
http://www.techpowerup.com/reviews/MSI/GTX_660_Ti_Power...
http://www.hardocp.com/article/2012/08/27/nvidia_geforc...

honestly i was a bit worried about the narrow memory interface before but as shown by test done by hard ocp GTX660 Ti are not that bad as people like to believe. may be it will be a problem on high resolution but as i mention above i don't plan on upgrading my monitor. not unless my monitor got broken  . plus i'm no AA freak lol. most of the time FXAA did just fine for me. and speaking about FXAA it is one of the bullet point why i want to stick with nvidia.

but what really in my mind was is i wonder if the card going to 'overkill' in my resolution and will my 2500K at stock setting are good enough to keep up with the gpu at such low res.

anyway i have to say thanks to you guys for any input you have given to me  

At 1600x900, you certainly won't be maximizing the potential of the 660Ti. May I ask: why are you thinking about upgrading? Is your current 460 unable to handle the games you're playing?

Don't play the overkill guessing game. That's an ideal problem to have. If you can afford a 660 Ti, don't downgrade with the potential of regretting it in the future.

the gtx460 that you currently have is usually more than sufficient for most games at the resolution you play at. so why the need for a new card.?