maybe your mobo and like you said your processor.. other than that it looks pretty good to me
I wouldn't upgrade anything right now. Your processor is perhpas the weakest link, but overclocked it won't hold you back at all.
Upgrade to the GTS G92$215 at Newegg.
Sound? If you only have a 2 channel setup then I would definitely upgrade for a 2.1 or a 5.1 setup.
A better processor would also be what I would say too.