And yeah...to add to discussion, SLI GTX690 is absolutely insane and really impractical, and here is why.

1. GTX 690 only comes with 2 GB of RAM per GPU, meaning there is 2 GB total ram with 4 GTX 680 GPUS!!! On a single 1080p screen it doesn't matter but if you want to use those GTX 690s to their true potential, you will run out of VRAM long before you "max out" their capability.

2. Scaling will be terrible with quad GPUs. You're probably at 2.5-3X better performance maximum, where a dial GPU gives you 1.5-2X and triple gives you 2-2.5X better.

3. You will hit a CPU bottleneck long before you git a GPU bottleneck on a single screen

Bottom line is, GTX 670 in SLI is the absolute maximum anyone will need for single screen gaming for the next 5 years. 4 GB EVGA version if you really want to "futureproof" your rig.

GTX 670x sli and 690 are pretty much identical in terms of performance. 

http://hexus.net/tech/reviews/graphics/39605-nvidia-geforce-gtx-670-sli-vs-the-beasttm/?page=2

GTX 670 sli is 200-300 cheaper though.

670 would be cooler and if your concerned about heat. and as for the  next 5 years, well two 690s would not be much help if there is major driver shift or continued increase in texture detail. try one of the 4gig 680/670 and add a second card at a later date. im using one OC 7970 and if i use one 1920*1200 monitor  even in the most demanding/ or poorly programed games the most vram used is  1.8 gb, and never any issues with frame rates . when in  3 monitors   1920*1200   (1920 by 3600)  monitors  in eyefinity and i do run short on ram occasionally if i spec everything out and frame rates dip every now and then, dial the settings back just a bit and im fine, when i add two more monitors and make it (1920 by 6000) ill add a second gpu. i don't think ill get a third the power and heat issues are just two much …. i doubt though the 8XXX or 7XX will be able to handle all the space with one gpu just yet 

I was thinking of building a small PC myself for the living room. Then I noticed you wrote APU.

I haven't kept up with hardware in the last 5years or so. What is an APU? and what you mean pair with GPU?

APU is the abreviation of "Accelerated Processing Unit". Basically it's a CPU with something else, usually a GPU, so when you buy 1 APU you are actually getting a CPU and a GPU all in 1 package.

When he says that he will pair it with an HD6670 it is because APUs can be used in conjuction with a graphics card. Now, some GPUs (and I think the one in the HD6670 is one of them), are so similar to the one inside the APU that you can enable Crossfire with them, getting more performance.

Yep.

I am still interested in the APUs especailly the new FM2 socket ones. But AMD is so secretive about it. They are supposed to be out in less than a month and we really don't have any reviews or benchmarks. Nor do we know what GPUs the new A12 APU will be able to crossfire with. Everyone is saying 30% performance boost, but I'll believe it when I see it...

I hope the secrecy isn't because they can't deliver like with Bulldozer.

Ah, so it is sorta similar to back in the day when mobos had onboard video (but were  shithouse).

This APU, I am guessing would have a decent GPU in it but guessing not as highend as a gfx card.

Since its AMD, would it be safe to say it be one of their old gfx card GPUs integrated into the one chip?

Are APUs good enough to play highend games on their own? if so on what setting in the game and approx frame rate? i.e. the high intensive graphics games like crysis and battlefield

Actually APU is quite high end tech. Definetly isn't one of their "old" gpus slapped on to a CPU.

Infact I think its the only area where AMD still can beat intel, low end graphcs and power consumption.

Obviously and APU plus a HD 6670 in crossfire wouldn't compete with a GTX 680 by a long shot, but they can be put in to a mITX motherboard, with a 300 Watt power supply and sub 500 dollar price tag with all components included. The best APU + 6670 should be able to play any current game at 1080p on medium or even high... forget about AA tho. :)

Here is a comparison video showcasing what to expect from an APU wich is a year old now. There is a better APU already available and the new ones are supposed offering minimum 30% better performance.