Would Greatly Appreciate Some Help With a New Rig

So I build a new system every few years and it has come time yet again. I work at Best Buy so I typically do the Intel retail edge purchase bundle when it looks good and go from there. This year they have a nice processor and a nice ssd but the motherboard isn’t so great and there is no discount on it anyways. So that’s where I have questions, I have decided to buy something other than the Intel extreme motherboard and I am looking at ASUS P6X58D-E or GIGABYTE GA-X58A-UD3R. I am leaning towards the asus based on past experience but I am open to recommendations. Also I don’t know what ram to use, the processor "Intel Core i7-970 Gulftown 3.2GHz 12MB L3 Cache LGA 1366 130W Six-Core Desktop Processor BX80613I7970" supports Integrated DDR3 Memory Controller, and triple channel ram and I honestly don’t know what that means or how to take full advantage of it. Also on the Asus what does "features Triple channel DDR3 2000(O.C.)" mean, not clear on triple channel or O.C.(I'm thinking overclocked???) This system is for gaming and burning disc's I do no video editing. I just want something I don’t need to upgrade for years. Thank you very much for any help you give me. My new rig is as follows

Intel® Core™ i7 970 Processor 6 cores – 12 threads, 12MB Cache,.32nm process technology
ASUS P6X58D-E or GIGABYTE GA-X58A-UD3R
PNY VCGGTX4601XPB X 2 SLI
PSU COOLMASTER| RS850-AMBAJ3-US RT
Intel® X25-M 160GB Solid State Drive
Corsair H70
RAM-Cmx8gx3m4a1600c9(8gigs 1600mhz)/Cmx6gx3m3a1600c9(6gigs 1600mhz)/CMX6GX3M3A2000C9 (6gigs 2000mhz) Not sure which one

For ram I could also go with 8 gigs of slower ram(1600) or 6 of faster(2000) not sure which is best.

Thanks again.