I've got a DELL Inspiron 9400 laptop
2.0 GHz Duo Core 2 T7200
Geforce Go 6800 Ultra 256mb
2gb 667 MHz ram
120gb 7200 RPM HDD
goes pretty well but with the release of all these new games that I dloaded in the past week such as ArmA, Call of Duty 2, C&C 3, Dark Messiah etc. its pretty well outdated when you crank up the video quality settings so I built a new desktop on monday and so far im very happy with it, especially the 8800 GTX it really hammers anything thrown at it.
My Gaming Desktop:
2.66 ghz E6700 Intel Duo Core 2 (planning on upgrading to Quad Core Extreme QX6800 once available in AU)
Nvidia Geforce 8800 GTX 768mb (ASUS)
4 gb 667mhz Kingston Ram
2 x 500 GB 7200 RPM Baracuda HDDs
Asus mainboard with all the goodies such as SLI and Quad Core support (even 8 core support but I don't think such processor exists yet)
Thermaltake Full Tower aluminium case (8800 GTX can't really fit in anything smaller then full tower)
Audigy sound card
... and all the other shit that doesn't really make much difference
So far my main test was absolutely maxing out Oblivion video quality settings and it goes very smooth and never skips a frame, whereas my laptop was very choppy. The price difference between a 8800 GTS and a GTX of merely $300 or so is well worth it I recon as its apparently 30% faster.