The motherboard shouldnt really be what governs what you do on your PC, thats the job of the processor, for games and vid editing the AMD 64 range are pretty decent. For that you will be looking at a socket 939 motherboard, there is also socket 754 motherboard but they are becoming quickly outdated. Stick with 939.
A suggestion for the motherboard, the Gigabyte GA-K8N Ultra-9, it is a decent price (look it up for yourself), it supports the newest SATA speeds, it supports PCI-e, DDR400. And gigabyte is a good make. Also, it is built on the nForce4 chipset, which kicks ass
In case your wondering where to go in RAM, dont look at DDR II because AMD 64 doesnt yet support. Standard DDR400, i suggest at least 1Gb since you'll be gaming and vid editing, perhaps the OCZ Premier Dual Channel Kit 2x512MB.
As for a video card, well, due to the gigabyte mobos PCI-e support, we can go for highend cards. Maybe an XFX GeForce 6800 GT PCI-E 256MB DDR3. Not too expensive in comparison to some. Check prices for yourself, hope all that helps
dragon2309
*EDIT*
bazzil do u live in adelaide?? if u do tell me i live in adelaide too
please stay on topic, try to help the guy, not ask him where he lives, that doesnt matter.