Acceptable Sump/Display tank turn over... ?????HELP?????

[ZachAttack]

OK guys I'm REALLY lost on this one...

I am upgrading to a 90 gallon tank with a 40 gallon sump. It will contain a skimmer section, return, and refug. I've read ALOT of threads about turn over... Some people say you want 50+ turnovers an hour!!!!! while others say 5x is more than enough. What are the advantages and disadvantages of each?? is either better or anything? If anything I've heard that high gph is bad because it increases the amount of microbubbles and adds heat to the water. So what am I looking at for differences??

All opinions are appreciated, but if you give me your opinion please substantiate it with reasons why you think it's better. THanks guys!!!