Hey all - posting to get an idea of whether or not it's going to be worth it to spend an extra hundred dollars on a mobo for x38 over a p35.  I'm planning to overclock but not pushing it to the extreme.  The two boards I'm comparing are both Gigabyte boards, and I'm wondering if I should really go with the x38 cuz of the rest of the build:
 
x38: http://www.newegg.com/Product/Prod [...] 6813128089
p35: http://www.newegg.com/Product/Prod [...] 6813128059
 
Here's the rest of the build, and suggestions are accepted and welcomed:
 
Case: Lian Li PC-60APLUSII http://www.newegg.com/Product/Prod [...] 6811112069
Proc: Intel Core 2 Duo E8400 Wolfdale 3.0GHz http://www.newegg.com/Product/Prod [...] 6819115037
RAM: OCZ Platinum 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066 http://www.newegg.com/Product/Prod [...] 6820227178
gfx: BFG Tech BFGE88512GTOCE GeForce 8800GT 512MB http://www.newegg.com/Product/Prod [...] 6814143118
 
Will be grabbing a 550W power supply and dvd writer from work, as well as using my current hd running 32bit xp until I invest in a new OS and HD.  Is it worth it to get 4 GB of ram or is it better to wait until I upgrade to Vista?

Looks like your on a budget.  Let me make a suggestion.  Change that Ram.   1066 really isn't worth it.  Go with 800.  Save some money, and put it into a better graphics card.  8800GTS 512.   You'll notice more difference that way in real world applications.   Why even look at X38?  Look at X48.    
P35 is solid, but  X48 is more Robust.  

For something as important as the motherboard I'd have to recommend the better of the two...which would be the X38.  Doesn't have to be the most expensive X38 but choose the X38 nonetheless, since its an option.
 
...and you did pick a nice one.  

I'm not really on a budget but I'm angling more for something that's a toy I can play around with than a serious, off the wall gaming pc.  I could go up for a 8800GTS but is it worth the extra $50 or so for something like that, considering when the new nVidia gfx cards come out I'll be looking into one of those?
 
Also I hesitate to go all the way to an x48 simply because it's another $100 for not that much added value.  Maybe someone can sway me on this, but is it worth it to spend that much more money at this point, before ddr3 becomes standard on mobos, for an x48 over an x38?

 
Sounds like the Asus X38 might be what you're looking for, minus the price.  It has all the toys you're gonna want in a motherboard, plenty of copper...and a price to match.    
 
So, take a look at this:  http://www.newegg.com/Product/Prod [...] 6813131219
 
That's a nice board and only $25 more than its Gigabyte competitor.  Want more toys?  How about an external backlight LCD troubleshooting display?  It'll cost ya but ....  http://www.newegg.com/Product/Prod [...] 6813131227
 
Now, however, you're in the bells and whistles department with advanced auto-overclocking features (that you, of course pay for)...Rampage Formula X48 ... http://www.newegg.com/Product/Prod [...] 6813131284
 
So, you've got to think about what you want and need, and are willing to pay for, because this will get you by just fine...
 
http://www.newegg.com/Product/Prod [...] 6813128089

I wouldn't - I just bought an X38.  I couldn't see the point of all that extra money for an X48 when you don't seem to get much in return.
 
My theory was that by the time I am ready to upgrade, Intel will have a new chip anyway, which will require a new motherboard.

I did a build a few weeks ago and choose the ASUS Rampage Formula X48. Its got a few extra features, which may or may not be valuable, depending on whether or not you use them. Its been very good with my quad and I've gone over 4ghz with ease. More to the point, to get over 4ghz, all I did was set the FSB higher and the voltage to the CPU and ram a bit higher, with everything else left on auto. Yeah, that sounds lazy, but that's part of what you get with a high end mobo.

 
+1