if you plan on having your computer last, it might be wise to invest in a X2 3800+. yes, its a 200 mhz difference. and yes, it costs like 90 bucks more. but for that money, you get 2 cores, a much better performance multitasking, and even some games like quake 4 show better scores on dual core then single core (where a 850 dollar costing 4800+ @ 2.4 stock beats a 1030 bucks FX57 @ 2.8 stock) with the latest nvidia drivers, and the ati ones get dual core support from cat 5.12 which should come along shortly.
in a years time, alot of new software will run much better on dual cores then single. games will too. and the much expected unreal engine 3 will make its appearance around then, and for that you can use anything processing power you can get your hands on.