Optical Drive: Sony NEC Optiarc 7170 SATA
At $35, the Optiarc 7170 is a very speedy DVD-RW drive. Add to this the convenience of SATA cabling, and you have a real winner.
Video Card: EVGA Geforce 8800 GTS 320 MB
There's really not much to say about the Geforce 8800 GTS 320 MB except that it's incredibly powerful for the price.
Compared to its 8800 GTX and 8800 GTS 640 MB brethren, the only notable performance difference appears at resolutions 1600x1200 and above. This does not mean that the 8800 GTS 320 MB can't handle some 1920x1200 gaming mind you, the GTX will just be faster.
For $280, there's no better videocard you can put in your machine, period.