Question : Problem: I need to choose the right motherboard upgrade, please review

I need help choosing an appropriate motherboard upgrade.

I have installed the basics for 20 years but the newest barrage of motherboard choices leaves me in a quandary.  Asus has always been my brand but I could use some help making my next motherboard decision.

My needs:
"      I dont care about over-clocking.
"      I like good but not best framerates in games (but not a gamer).
"      I need medium to fast video editing.
"      I dont need fancy onboard audio but it needs to sound good.
"      I dont like spending a lot of money.
"      I want a 3 year longevity (through minor upgrades).
"      The board must have e-Sata connections for my external drive.

My confusion:
If I dont use two video cards will the SLi boards, because they are newer, reap better benefits (ie 16x cards)?

I read this statement on the net and it confused me since most motherboards use them&Avoid motherboards with JMicron components at all costs.  What are the thoughts on this?

How soon will DDR3 replace DDR2 memory&does it matter?

Is it really better to use DDR2-1066 over DDR2-800?

My initial research and potential MBs:
Please review these options and give me warnings, advice, or other products that might better suit the criteria above (I like spending less).

Asus P5N-E SLI (119.99)
MSI P6N SLI Platinum (109.99)

Answer : Problem: I need to choose the right motherboard upgrade, please review

First, a few general thoughts ...

".. I like good but not best framerates in games (but not a gamer)." ==> You do NOT need an SLI board.

"...  How soon will DDR3 replace DDR2 memory&does it matter? " ==> DDR3 will eventually have better performance; but at the moment the high latencies make that difference small ... and absolutely NOT worth the price difference [especially bearing in mind that "... I dont like spending a lot of money."]

"... Is it really better to use DDR2-1066 over DDR2-800?" ==> The benefit is very small with current CPU's.   If you're not an overclocker, I would NOT spend the extra $$ for the 1066 memory.

"... I want a 3 year longevity (through minor upgrades)." ==> The most important thing to ensure a relatively long lifetime (without feeling "obsolete") is to ensure the board supports the 45nm Intel chips at 1333MHz FSB.   This will allow a very nice performance boost with a simple CPU replacement.

"...  I need medium to fast video editing." ==>  This means you need a fast CPU, plenty of memory, and a reasonable (but not top-of-the-line) video card.

I would NOT buy an SLI chipset motherboard based on what you've described.   For a rock-solid, stable, upgradeable (to future 45nm chips) motherboard, I'd get a P35-based motherboard.   Since you like Asus, this would be an excellent choice:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131189
... other excellent choices are:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813121314 (Superb board; includes an esata bracket)
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128059 (Another superb board; but does not include an esata bracket -- you'd have to buy one for ~ $5)

With any desktop board, the memory subsystem is more reliable if you only install 2 memory modules.   So I'd buy 2 2GB modules (4GB total).   This is an excellent value (I've used these modules several times):   http://www.newegg.com/Product/Product.aspx?Item=N82E16820211188

For the CPU ==> The E6750 and E8400 are the two best values at current prices for Core 2 Duos.   The Q6600 is the best value in a quad core.   Any of those would be an excellent choice.

For your video card ==>  The best value in a performance video card right now is the 8800GT.   I'd get this card:  http://www.newegg.com/Product/Product.aspx?Item=N82E16814130318

With the Asus motherboard, an E8400, 4GB, and the eVGA card I've suggested you'd have an excellent system for just over $500 (plus case, power supply, hard drives, etc. ==> since you indicated this is an upgrade, you may very well have all of those items).    This should easily last 3 years ... and if, along the way, you wanted better performance, you could simply swap the CPU for one of the newer 45nm quad cores Intel will be releasing later this year [they've already released a few ... but the prices are still a bit high --> not consistent with "... "... I dont like spending a lot of money." :-) ]