I also switched from a q9550 (3.8ghz) to an i7 system, (stock at the minute) primary use is gaming, i wanted to have the option of sli/xfire which x58 offers, also being a newer platform i fancied giving it a try out.I personally went from the Q9550 3.4ghz - 17 920 -3.7 - 4ghz. I have noticed good gains in some areas i use my system for. Everyday use and basic stuff hardly anything except quicker loading etc.
Its not a massive upgrade path for the cost , however it puts you on the latest platform with the more up to date tech.
McT
so you reckon the q9550 won't be bottlenecking newer gpus within say the next year or so?