Is there anything I can improve with my system

I built the system a while ago. It's been running well enough. Just wondered if there is anything particularly weak that would be worth upgrading to get a large performance boost.

Motherboard - Gigabyte GA-EP43-S3L
Processor - Intel Core 2 Duo E7400 LGA775
Graphics -1GB SAPPHIRE HD4870
RAM - corsair 2x2Gb 800MHZ
PSU - OCZ PSU 700SXS STEALTHXSTREAM 700W
OS - MICROSOFT WINDOWS VISTA HOME PREMIUM 64BIT
HDD - SEAGATE BARRACUDA hard disk
Case -Coolmaster 335 case

Am just curious so upgrading isn't a major priority.

Thanks.

Switch over to AM3 if you wanted to get some future upgrade paths.

Phenom II X2 545 3.0GHz - $87.99

ASUS M4A79XTD EVO 790X AM3 - $119.99

Patriot G Series 'Sector 5' 4GB(2x2GB) DDR3-1333 - $89.99

Subtotal - $297.97

Well he could get a Phenom II X3 710 2.6GHz for $109.00.

So the Subtotal would be $318.98

Buy a decent cooler and overclockMonsieurX