512*2 is cheaper than 1GB, hope you understand
Don't buy ATi Rage, it is pure crap. Your better off with a mid-level GFX card and 1.5k more for a TV Tuner card. You can purchase any USB pen drive and it will work with all computers bought in the past 4-5 years.
A DVD Combo drive is one that writes CD-Rs and RWs and reads both CDs and DVDs, good value for money and a Samsung drive will cost about 1.8-2.0k
Do mention where you live so other members can give more accurate pricing...