It really depends on your budget , patients and gaming wants.
The best G75vw imo is one with at least 16 Gb ddr 1600 or more, 1 SSD hard drive plus standard drive, 3D display (120Hz at 1080) and a gtx670m gfx, but your going to pay . There are about 4 basic versions with a multitude of drive and memory configurations.
The main difference I think being ; 660 or 670 dedicated graphics. 660 having 2G memory 670 3G , plus difference in architecture (performance/heat) Type of display , quality and style. ie 1080p at 120Hz (3d capable) or standard 1080p 60Hz. Type of hard drives 5400 rpm 1 Tb , 7200rpm 750 Gb and SSD's 256Gb or similar. Amount and type of memory, 8Gb , 12Gb 16Gb memory at 1600 , others by request Brand of wifi installed, Intel or Atheros All cpu's were the same , at least here in Australia at the time I got mine
I started with a general budget and worked out what I could get with what was a available in my area for the best deal. Ended up with a G75vw with 16G ddr 1600 , gtx670M with 3 Gb , 2* 1Tb hard drives (I wanted the internal space) 3D capable 1080p 120 Hz display . Payed extra for a 3 year unconditional replacement (not fix , replaced if not fixed same day in store)
I haven't had any of the problems listed here in the forums and would definitely get the same again if I had too. I looked at a few laptops , Toshiba , Samsung, Msi of similar specs and at default settings I believe Asus had the best and quietest cooling. Price wise within 5% of each other at least in my area.
The 670M beats the 660M in about 95% of all tests everytime, you can overlcock both of them. The 660M does pull less power and runs cooler and possibly better support due to its newer architecture ( I mean driver updates may give better performance increase % wise in the future).
This probably hasnt made things any clearer, all I can say is from my limited experience you cant go wrong with a G75vw baught from a reputable retailer