Alrightly then, im approaching the date when i will buy my new system, so i will just post what i've decided to get so far to make sure i haven' made any dumb choices.
Other information: I'm planning on overclocking the Q9450 as much as possible, hopefully up and beyond 3.6ghz (heard good things about FSB and the P45 chipset). Also, im shooting for a total of 1.5k USD final after taxes/shipping. Although i've linked all of these from newegg and it doesn't add up to less than that, i can find them on various other sites (already did) for lower prices/no tax (i live in california so i get tax on orders from newegg)
From what ive been reading of the reviews on Newegg since the Antec 1200 came out, its nothing grand. It definetly dosent follow in the footsteps of the 900 as far as quality goes. If you want a full tower check out the new Coolermaster Stacker re-re-re-release with the full unblocked side window, I think its aorund $175. Also the Cosmos is nice but expensive.
I currently own the ASUS P5Q Pro, and after some decent troubleshooting and a BIOS update from the release, all the problems I was having with heat and overclocking are gone. The only difference between the Pro and the E is the passive cooling on the mosfets and NB, the ones on the Pro are very, very insuficient, I took them all off and replaced them with Thermalright heatsinks for the 2 mosfet zones and the NB. However the cooling with the E might be better, barely. Regardless its a good board, but be warned about the hot NB, mine was hitting 63c with the stock piece on my 3.0ghz OC, with this thermalright it never tops 45.
Also snag the VisionTek 4870 if you can, Lifetime Warranty Everything else looks fine, a build very similar to mine, im using 1066mhz Reapers myself, but I have the Crossfire branded ones, $55 for a 2gb set. By the way Ill give you an important heads up here since we are using the same board and you are considering Reapers. The Xigmatek cooler WILL fit on either way without contacting the Reapers but make sure you put it on and the fan on before you put the ram in, dont make the same mistake I did and have to swap crap out 2 and 3 times.
If you're going to spend $200+ on a case, nothing beats Lian-li.
http://www.newegg.com/Product/Product.aspx?Item=N82E168... Is similar to my PC-G70 and i love it. Room for two PSU's is a big selling point for me as it's ridiculous to spend $200-$300 on a power supply to power gpu's stabily when you can actually run the GPU(s) off a seperate supply or the Hard disks fans and similar things.
You can buy a 5.25 inch that takes up 3 of the 6 bays, houses 4, 3.5 inch disks with a 120mm fan in the front to keep em nice and cool, all of case panels are replaceable, upgradeable so you can mod em yourself or add extra fan holes to the top and sides, the rear panel is replaceable depending on what route you want to go with PSU's and fans.
Then of course are the 5.25 cd/dvd bezels and bay covers, which look quite spiffy.
Basically you can take mod/replace the case down to it's frame, then you can adjust the frame as well. The full towers are around 8''x24x22, big enough for a grown man to sit in when it's empy, light enough to carry one handed but sturdy enough to stand on top of.
That is one that looks similar to the antec, though has 9 5.25 bays with a 140mm fan vent in the top. But honestly you would probably do well with any of the Full Tower cases. I've built dozens of computers in a dozen different cases made by different manufactures. Lian-li is the only one of those i've actually found enjoyable enough to work on to merit buying a second.
I have the G.Skill 2x2 1066mhz kit you listed there, i'm quite happy with it, have it running 5-5-5-12 1066 on 1.87v (rated to run 5-5-5-15 @2.1v) so i'm sure it's got some overclocking room, would certainly opt for 4 sticks of that over the 2 of the corsair.
As for board and chip, well that's your call. I'm more partial to DFI, best overclocking boards IMO and nothing ore solid at stock in my expeirence, though gigabyte is good too.
ASus has been iffy for me. Only really reliable thing has been DFI and with them faring so well with intel boards i really would reccomend going with the newest most expensive dfi xfire board that is compatible with that cpu. The motherboard is the one area where it's worth spending the extra cash. Especially if you're going to overclock.