I'm in a fix... Do I need DDR3?

I've got a Pavillion m8100n that I'd like to upgrade so I went out and got:

AMD Phenom II X4 940
G.SKILL 4GB DDR2 1066
ASRock A780GMH/128M AM2+/AM3 AMD 780G

I'd like to repurpose the box/hadrdrive/dvd burner - like to get a micro atx mobo. So these things are shipping right now, but now I got on this Tom's Hardware site and now I'm wondering if I should go with a straight AM3/DDR3 board?!

I'm looking at newEgg and they have AMD II X4 955 Bundle with CORSAIR XMS3 DHX 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 for only about 50 bucks more than the 940/G.Skill.

Only thing is the only micro ATX motherboard that's AM3 is this DFI LP JR 790GX-M3H5 AM3 AMD 790GX that has only one review.

I'm sort of newb so it seems like I should stick with stuff that has a lot written about it.

But I also don't want to buy a new mobo in a year to upgrade cpu/memory...

Any help much appreciated. I guess I should add that my primary use is graphics / video editing / photoshop. I need a fast quad to edit avchd footage.

Video Editing - DVD/Mpeg2 Encoding - AVCHD editing - Photoshop

Right now I've got a AMD 6400+ / 3 Gig RAM but want to upgrade since sometimes I have a bunch of Adobe CS4 applications open at once. The box is almost always encoding something or other....

Well theres no performance difference between ddr2 and ddr3 with AM3 processors so its your call. If you want maximum upgradabiltiy, go with AM3, if your going to keep the system a few years before you upgrade again, stick with what you got.