Futureproof, quality motherboard for Phenom with nVidia SLI

I'm building a new computer on a tight budget, with plans to pump more money and upgrade it in the near future.
Basically I'll go for an Athlon 64 X2 5000+ Black Edition which I plan to moderately overclock at around 3200Mhz.
And buy a nVidia 8800GT video card.

In the near future, when Phenom will be more mainstream and prices will drop, Im thinking I could replace the CPU and buy a second nVidia 8800GT card and go for SLI.

Thing is, I need to find a quality, reliable motherboard that supports both Athlon 64 x2 and Phenom while it supports the nVidia SLI and not the ATI crossfire.

So far I got my eyes set on a Gigabyte GA-M57SLI-S4 (rev. 2.0) which seems to have the specs, but all in all people are complaining of the northbridge running hot and a higher than average failure rate after a month or so. I'm not very comfortable with this since I need to be able to overclock it.

Would you recommend this motherboard or another?
Do you find this to be a good upgrade plan?

i know it sounds tough. but this unlocked cpu can be upped to 3200Mhz with decent cooling and without complicated trial and error.

there are some guys there who managed a 3400Mhz but with hardcore cooling and very very customized settings for voltage and high-end memories. which i dont plan to delve that deep.

regarding the cpu support, for this board, gigabye site says

"*Note: If you install AMD AM2+ CPU on AM2 motherbord, the system bus speed will downgrade from HT3.0(5200MHz) to HT1.0(2000 MT/s) spec; however, the frequency of AM2+ CPU will not be impacted. Please refer "CPU Support List" for more information. "

How much impact would this have on the perfomance?

oh, its an adverb. =)
"moderate" should have been the word.
honest non-native english mistake.

i totally understand the point, why buy an athlon when the next generation is here?
well, it has to do with the price, im building the computer on a tight budget.

i can get the Athlon 5000+ Black here at around $110 while the cheapest Phenom is double the price.
but the overall performance gain is nowhere near the double.

in games the difference is somewhere in between 5 - 15FPS, in Photoshop the Athlon beats the Phenom and there are very rare cases where Phenom is double the bang of the Athlon. And all that without overclocking.

Keep in mind, the cheapest Phenom is 2.2Ghz while an overclocked 5000+ reaches 3.2Ghz. What it lacks in cores and advanced instructions is gained back through raw power.

The Phenom is better, but the bang for the buck prize goes to Athlon.

So the 5000+ should be decent for about an year, an year and a half. After that, sure, I will buy an $100 Phenom.

That's the whole plan.