My two cents -- Quality over quantity!
I think its a bit dangerous to get caught up with real "numbers" -- as in number of hours to prepare and stuff. It all depends on the individual and how comfortable he/she is with the material. I know a couple of friends of mine who studied less than 100 hours (2 months about 10-12 hours a week) and cracked the exam. I also know of a couple of others who spent more than 6 months and tons of time -- and still did not do very well. It's all relative. Someone who has been away from school might need more time to refresh Math skills. Someone who writes detailed reports and academic papers might not need much help with verbal. Some people are naturally gifted at taking standardized tests, while some others are very poor at it. And as we can see on these forums and from general experience -- lots of the internationals from Russia, India, Korea etc seem to just blitz the quant, but understandably verbal is major challenge for them. Lots of locals seem to struggle with the Math more -- but are fairly decent on RC and SC.
In any case -- 200 hours seems like a LOT of time. Plus I am not too sure how much people can actually "study" for the GMAT. I mean, it's not a theory exam -- its somewhat like an IQ test. I am not too convinced that just doing scores of problems is going to yield better results.