Yes, but it won't be cheap. Frys had this cpu for $200 the other day, same as microcenter. 4 gigs of 1600 ddr3 is around $40-$50 after rebate. Boards start at around $170. Sell your old stuff first; if you don't get any decent offers, I would keep running it as is. It's not that slow.
Some games now use quads, and certainly more will in the future as they become more mainstream. However, you are looking quite easily at a $400.00 upgrade by the time you get a new motherboard, cpu, and other things that we happen to get sucked into buying. If you have $400.00 that you aren't afraid to loose then sure. Might I suggest this path though: Scour ebay for some of the core 2 quads. Anything from a Q9400 up should be as easily clockable as the e8500, and will give you more performance on the cheap for a while. The core 2 Quads are still a force to be reckoned with.