Well, maybe the third time's a charm, but as has been said twice already, your video card is by far the weakest link in your system. 6600gt is the minimum for playing the latest games. At decent settings Cod2 or Fear will bring your current system to it's knees -- in fact many of the latest games don't notice a nice CPU much, it's all about the GPU baby! Of course you could avoid playing the GPU hungry games now and down the road, but since you started this thread asking for comments on how your system fared in a graphics test, I hope it is dawning on you that the only way you are really going to improve your graphics performance is to upgrage your graphics card.
Lastly, even though adding memory to your system is a good idea, don't fall into the trap of thinking 128mb isn't enough for your GPU. This is the card I have in my sig:http://www.newegg.com/Product/...asp?...N82E16814122201
With only 128mb, it has done a pretty nice job of handling anything I've thrown at it (Hl2 Fear cod2 far cry King Kong etc) Sure I'd love to bump up the resolutions and completely max out the settings on everything, but since I can on most everything and the low power draw and quiet fan are perfect for a SFF system, that 7800GTX is going to have to wait. (That card might easily end up in another build down the road though, cod2 is that good.)
Anyway it would be interesting to see your score after you've upgraded your card.
Antec Aria SFF case w/ 300 watt PS
Sempron 64 3000+ o/c to 2.25, stock hsf
ASRock K8NF4G-SATA2 Micro ATX mobo
Wintec AMPO 512x2 3200 (250 fsb/ht)
Samsung hyperquiet SP1614N 160GB HD
AOpen Cocoon wireless RF KB/mouse
Leadtek PX6600GT TDH Geforce 6600GT
128MB GDDR3 PCI-E x16, o/c to 564/1160