You shouldn't be a guinea pig for NF5 mainboards, it's not out yet, unproven, unknown, unsupported etc, unless you feel like being a hardware tester of course.
I read some reviews on NF5 and it looked a bit weird, a lot of useless features just to provide more features ?
I wouldn't get the E6300 or the E6400 cpu, there just isn't enough price difference between them and an E6600 cpu. The E6600 has a cpu multiplier large enough to be a useful overclocker, the lesser conroes are going to be limted in their stock performance and won't be nearly as easy to overclock to useful speeds for future apps.
Only a very few mainboards will clock 450-500mhz successfully, and that is with experienced people as well. Joe Bloggs might not be as successful.
The OCZ ram is high priced and old hat. Until OCZ release ram with tighter timings, they are only going to catch the "sucker market".
Look for something like G.Skill PC6400 4-4-4-12 "PK" designated ram or "HZ" if you have a few spare dollars. Ram prices just went crazy so I'm not sure what the damage is going to be.
The 7900GTX/GT series of graphics cards has been plagued by problems with high return rates and some users are on their 5th warranty card, just be aware of that with some manufacturers having more than their fair share of problems. I'm not sure about the Asus card you chose, maybe some research is prudent?
Recently, the 7900GS was released, and this card is substantially cheaper, it fills the market slot that the 7900GT was meant to provide, a high end card at a cheap price. Demand, supply problems and profiteering killed the hopes we had for the 7900GT as the "card for everyone", perhaps the associated hardware problems with the series is just so much payback by Karma?

The 7900GS looks like it's a solid performer that sits just under the 7900GT performance wise. Let's hope it doesn't have the problems the big sisters had.