Your price estimates are unrealistic and serve as unfair basis for comparison.
First, the x58 intel motherboard for $220.00 is much better than most motherboards for the q9550 in the $150.00 range. Not only is a quality motherboard essential for maximizing performance by faciltiating stable overclocks, it is also necessary to supply sufficent voltage to your processor and ensure stabiltiy issues. A 150 motherboard may well serve the average user's purpose, but those users are better off purchasing the Q6600 for $200.00. Here, neither the intel x58 or the 150 mainboard should be considered sufficent, as neither will allow you to maximize your CPU. A better basis of comparison would be the EVGA x58 (I7) V. the EVGA 780I ultra (Q9550). If you are going to invest 300+ in a processor, it would be shame to purchase a motherboard that cannot support, or will bottleneck nearly every component. Here, the mainboard price is 300 for the X58 and 225 for the 780i.
Second, in regards to the processors, the I7 920 outperforms the Q9550 in nearly every benchmark. This is due to better technology as well as efficiency. More on this later, but the Q9550 costs $350.00 and the I7 920 can be found for 300.
So far for the EVGA X58 and the I7, your're looking at a combined total of 600 and for the 780I ultra and q9550 you're looking at 580 - the edge leans towards the I7 as the performance difference is signifgant.
Third, Ram. The x58 chipset supports Triple Channel DDR3 ram which is signifgantly more expensive. For 6GB of quality triple channel ram, you're looking at spending an additional $300.00. This can be expanded to 12gb of ram on most of the x58 chipset. Compare this to 8gb of ram DDR 2 (maximum) for around $150.00. Here the price difference is more signifigant -- while the core I7 is better than the Q9550, Triple Channel DDR3 Ram is MUCH better than Dual channel DDR2 ram. The reason that DDR2 ram has become so cheap, is because it is becoming dated. Within the next two years, DDR3 prices will drop and DDR2 will start to become phased out. This is where system builders have a desicion to make:
Desicion one: Q9550, 780I + 8gb DDR 2 = 730
Desicion two: I7 920, X58, + 6gb DDR3 1600 Mhz Triple Channel = 900.
The difference in price is $130.00. This price is less than what you expressed and also points to another conclusion --- you're not going to be building a Q9550 system that can take advantage of the processor for less than 700. This is important, as if you're already investing that much in only three components, it would seem you should be in a situation where you can invest 900 for a MUCH BETTER system.
Desicion two is the better investment for at least two reasons.
First, it can be expanded. Intel will not make much improvements to the Core 2 Quad series - while there may be modest increases in speed, the next year or two, you're not leaving yourself much room for improvement. The Core I7 line will continue to be support for the forseeabe future, so, with desicion two, in three years when you are ready for a new CPU, you can simply upgrade the processor as opposed to starting from scratch - the moral of this story is that in the long run, the upfront cost will more than pay for itself.
Second, PERFORMANCE. Compare the benchmarks of the Core I7 x58 chipset with DDR3 ram v. Quad Core w/ DDR2 and you'll see a SUBSTANSIAL difference. If you're going to be spending this much money on a new computer, it makes little sense to get a system that is already outdated and will soon be unable to perform sufficiently for games / software in high resolution / high CPU load scenarios.
Now, in regards to this being a test year for the I7 - that may be true. Although this seems like more of a reason to hang on to your old system and wait a year than to invest in an outdated, new system. Also, I think this worry is exxagerated. The I7 has experienced a relatively stable release - I don't see the x58 chipset posing problems that the average system builder, with some experience, cannot overcome.
Interested in your thoughts and comments,
Jason