I am looking to squeeze more juice out of my rather budget ASROCK 4CoreDual SATA2 board - it supports Core 2 Quad Q6700 and a Core 2 Extreme QX6700 - both have identical clock speeds and cache which leaves me with one question.
 
Is there any point in me gettin the Core 2 Extreme version when I can get the same speeds and cache from a Core 2 Quad?

Core 2 Extreme has their multipliers unlocked, and having a better binned die. Therefore you can overclock QX6700 higher than the non-extreme version.
 
Other than that, those two should be identical.

The Q6700 has a multiplier of 10. That already allows some spectacular overclocking. I think you're better off with the Q6700 and using the rest of your cash for other upgrades.

I agree.
Deppending on your budget and the price of a QX6700 (I assume it costs more than $500) a Q6600/Q6700 with good cooler (XIGMATEK HDT-S1283 for $40) and a good motherboard(GA-P35-DS3R, P5K-E,...) would be way better value and offer better performance when overclocked.

Why waste money on a dated Extreme cpu? Try the cooler, faster Q9300/Q9400.  
 
Btw, Nehalem will be out in months. Worth waiting.
 
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Intel Q9300 3.0GHz
Nvidia 9800GTX  
4GB DDR3 PC16000
64GB SSD
Windows Vista Home / FreeBSD 7.0 + KDE 4
www.everypot.com

The problem is q9300 use 7.5x multiplier, which is a major difference to q6700's 10x.

Because that is all my motherboard will support at this moment. This is for the family PC which everyone uses so I want it to be fast but I don't want to spend money stripping it out completely. I am only trying to squeeze as much juice out of it as possible before the top of the line chip is no longer available - the rest of the cash is going towards my rig which will very likely have DDR3 RAM, PCI-E 2.0 and one of the newer Core 2s with 3MB of cache on each core.  
 
As for the Nehalem, since I'm not that knowledgeable of the processor market, what does the Nehalem offer that is worth waiting for?

Your new rig could be much better if you get DDR2 instead of DDR3 and use the savings to get a great video card or two.
 

^Agreed. DDR3 offers poor value.
Buy 8GB DDR2 and a nice graphics card if you want to treat yourself.

Do NOT get a Q9300. Opt for the Q9450 instead. The difference between extreme and non extreme processors in the 6 series is 584 million transistors vs 410 million transistors. In fact when you look at Intels white papers you wonder if the q9300 and q9450 aren't much more than dual cores (also having 410million transistors) split into 4 instead of 2. Personally I spent the money and bought a QX9650 oc at 4GHZ with raid. VERY happy.

P.S Asrock's 4CoreDual-SATA2 mobo doesn't overclock quads. Even struggles to get to 291-294 Mhz FSB on Duals. Think of a new mobo if your planning on overclocking, before the CPU upgrade.

this is for the family rig - overclocking is the last thing i want to do - i am aware that this board has a 5% decrease in FSB when using Quad cores - although im unsure as to how severely this will affect my performance.
 
So for the ASrock ill just go for the non extreme processor rite?? I guess the extremes are for overclockers.
 
And the new rig I'll choose the Q9450. uutorok you mention that the Nehalem is worth waiting for? What is so good about it?