Also, my rig right now includes:
gigabyte ga-ma780g-ud3h - $80 (after $10 mir)
amd phenom II x4 920 - $140 (no mir)
hitachi 1TB 7200 - $80 (no mir)
bfg gtx 260 OC - $126 (no mir)
OCZ 700W PS - $75 (after $25 mir)
4gb 2x2gb OCZ ddr2 1066 ram - $45 (after $10 mir)
and I shoved it all into a coolermaster elite 360 (smallest atx case around) using a sawzall - $40 (no mir)
That's IMHO a complete, blazing fast computer setup for a grand total of $586, with $631 upfront before MIRs . If you need a monitor, they have a 2048x1152 great 23" monitor for $200 after 40 mir. I bought it all at microcenter, recently so you can even get a nice easy way to return some of it as opposed to ordering from newegg with their restocking fees.
There was a crossfire capable version of my mobo with the 790gx chipset for $130, ive tried sli and hated it and wanted the gtx 260 anyway instead of ati so i didnt bite. But thats always an option, and it has heatpipes for better overclocking.
Let's compare this to the i7 computer i just helped my dad build.
core i7 920 - was $230 or more, now $200 microcenter
asus p6t deluxe mobo - $289
ocz ddr3 1600, 8 8 8 ram - $100 (after 20 mir)
xfx gts 250 - $150 (after 20 mir) (can get galaxy 250 at $99 now)
(OR ati hd4870 that we returned, too loud- $180 (after 20 mir)
ocz 700w ps - $75 (after 25 mir)
seagate 1.5TB 7200 - $120
coolermaster cm 690 case that i bought on black friday - $90 ($110 now)
Now, the cheapest x58 mobo they have is a gigabyte at 185, with 20$ MIR. so you're talking about $100 less if you switch to the cheapest mobo.
So, you're looking at $1054 for what we built, after upfront before MIRs = $1119. If, you instead want to limit yourself to no choice for the mobo at the cheapest mobo i can see, the 1TB from up top, the galaxy gts250, 200$ for the i7 now, then you will spend $859. Note, that is after MIRs so its above $900 upfront, and includes the more expensive case that unless you like to use a sawzall and get a crazy small case like me, you will need to spend 60-90 on a case likely. Also, this is without the monitor too.
Anyway, after all that shit, my point is, I have this nice little speedy quad core, gtx 260 computer for probably $586 bucks, even though i added in some stuff that I already had bought awhile ago because who buys all new components at once?
Lets assume you just want to upgrade from a dual core like i did since i got that a few years ago, well then you probably already have the ddr2 ram, so lets use that, and you might already have the video card, hard drive and case and power supply. Between the i7 and the phenom, I'd say you could get away with just upgrading the mobo and the cpu for the phenom, so you could get the good $80 mobo like me, the phenom II x4 920 for $140 and you just spent $220.
If instead, you'd like the i7, you spend $200 minimum for the i7 at microcenter, $185 for the cheapest mobo available and $100 for the tri channel ram. Even if you only wanted 4GB of ddr3, thats a waste because its still $70 and you dont get the triple channel. So that's $485. Even if you needed the ddr2 ram for the phenom, and REALLY wanted to just get the 4gb ddr3 if necessary, you're looking at $260 vs $455.
Now all the pricing differences aside, I was hesitating to get the i7 because of the need for ddr3 alone. However, one thing not a lot of people recognize is that the lga 1366 is made just for the i7s, so when i8 comes out or whatever's next, bye bye motherboard.
Instead, AMD likes backwards compatibility, so if/when AMD comes out with a bleeding edge AM3 cpu that rivals the i7, guess what? You can go ahead and keep the AM2+ mobos because they support AM3 cpus. Just the possibility of that, even if it would limit my precious new amd cpu, made me go with the AMD.
You could even say im making a bad price comparison between the i7 and the phenom, because the phenom is in a lower class that instead competes with the quad cores, but again with amd mobos you can possibly upgrade while intel mobos are locked to a specific type of proc which makes all the difference to me.