I need suggestion for 6GB 1600 or 2000 memory.

That's a bit much. I would not speed a extra 70$ just for minimal performance unless you got money to kill or you are like to do benchmarks.
I would get these:
http://www.directcanada.com/products...acture=G.SKILL
http://www.directcanada.com/products...acture=PATRIOT

Theres a seller on TPU that has some Kingston HyperX 2000mhz for $170. http://forums.techpowerup.com/showthread.php?t=108467

1600mhz OCZ Platinum should be fine
any over 1600mhz will show minimal performance gain
http://www.tomshardware.com/reviews/...7,2325-11.html

How about this set, on the Canadian newegg:
Geil 3x2GB 1600 CL7 at 1.6v
Only $164, much better deal.

So basically, 1600 memory is better for the buck?

I highly recommend the Mushkin DDR3 1600 Redline kit for some really low timings and nice overclockability. There are 2 variations, one of which may have clearance issues with some cpu coolers.

I ordered the OCZ Platinum DDR3 1600 7-7-7-24 b/c the multiple reviews i read showed it overclocked far better than any other kit in that price range. Once i get it, i'll probably leave it at 1600mhz but tighten the timings down as far as possible (CAS5 if possible), since what i've read is that the core i7 can reach higher memory throughput with lower-latency once you hit the 1600mhz mark. (vs higher latency DDR3 1866 or 2000 for example)

EDIT: Here is the OCZ OCZ3P1600LV6GK DDR3 PC3-12800 1600MHz 6GB Platinum XTC Triple Channel Kits i ordered.

There was a thread on here that talked about timings vs speed.

IIRC speed beats timing. So you should always go for the higher speed.

EDIT: Here's the article
http://www.overclock.net/intel-memor...her-speed.html

I am thinking to go for OCZ gold 1600 8-8-8-24 for ~170CAD.
Any comments?
Thank you

Just pulled the trigger on these!

I have decided, I am ordering this one:
OCZ Platinum OCZ3P1600LV6GK 6GB DDR3 3X2GB DDR3-1600 PC3-12800 CL 7-7-7-24 Triple Channel Memory Kit
Thank you all for the support and suggestions.

You should get these http://www.newegg.com/Product/Produc...82E16820231254 they downclock to 6-7-6-18-60-1t and run smooth as butter.

Does anybody knows how much can you downclock OCZ Platinum 7-7-7-24?