Better cooling solutions?

Cooler Master V10 is better for better air flow and cooler temperature but will be hard to add new ram beacuse it covers the cpu and the ram slots

As i7s are pretty hot, I recommend you get either top end air cooler(e.g. Prolimatech Megahalems/Megashadows) or any water cooler that are better than Corsair H50.

Planning on overclocking?

If no, the V8 is good enough.

If yes, get the V10 and start budgeting a water cooling system.

V10 is way too expensive compared to it's performance. Would not buy it. It's gigantic too.
What clock frequency are you aiming for? Prolimatech Megahalems is a decent cooler which allows you to hit 4GHz, on the condition that your chassis has really good cooling. This means a full tower chassis with lots of room around the cpu.
Then you really don't need an expensive V10 or water cooling. I OC'ed my 920 to 3.8G with the aging but not weakening TRUE and I get 65°C at load.

Or you can do that too.

thanks friends for your reviews...... i think v8 would be better for temporary use....coz i'm not going to over clock my system.....first i'll get some water cooling solution then i''ll overclock my system in future.....

i think v10 cover more space on mobo....problem is that it will distroy my ram...i have
CORSAIR DOMINATOR DDR3 TRIKIT 3X6G-1600 (2GBX3)... :-(..

what you say about v8 coz i'm not going to oc my system..

WAIT Don't get get water cooling, you really don't need water cooling to get a i7 to 4.0ghz in my opinion, and usual OCers aim for that mark. In my opinion a good high end air cooling is better than putting alot of extra money into water cooling. The Prolimatech Megahalems Rev. B, Venomous X (or Venomous X-RT this just has the AM3 brackets and a fan), and or the Noctua NH-D14 is a better choice with money savings. I think that the Venomous X is the best deal as it can keep the i7's very cool. And the price a lot cheaper than the NH-D14 for very close performance. Since you just said that you don't plan to OC just yet it's a good prep for the future, with out having to spend a whole bunch of money on water cooling later on. And when you get the Megahalems or Venomous X remember to get two high CFM fans like the CM R4's which are quite and high CFM, that way it'll keep it extra cool.  

From what i've gathered reading reviews the CM Hyper 212+ and CM V6 GT are the best performers/value in CM's line-up.
Other top performers are previously mentioned like the Megahalems and VenomousX i would also throw in the Thermaltake Frio into the mix as a contender.
For fans i would add a high quality fan like Scythe S-Flex,Noctua,Nexus, if you buy a cooler without included fans.