Below are the components I'm thinking about for my upcoming build so far. I'm not totally set on the motherboard, though, so I've also listed a separate configuration that might be more worth the money.

Case: Antec Sonata III, $125
PSU: 500W, incl. with case, $0
HDD: 320GB WD, $65 (this will probably change, I just quickly found a compatible hard drive. Whatever I go with will probably be about this price.)
GPU: HD4850, $170 after MIR
RAM: OCZ Platinum 4 GB (2x2GB) DDR2 1066, $85 after MIR
CPU: Q6600, $210
Motherboard: Asrock X48, intergrated WiFi (important), Crossfire ready, DDR3 ready, $230
Total: $885 plus shipping (Newegg says it'd only be $10 to ship it all, seems low tho)

However, I'm not entirely sure that I'm going to end up using Crossfire.
Here's what I might do different:

GPU: HD4870, $300
Motherboard: something like the Asrock P43 (DDR3 ready, no Crossfire), $90
http://www.newegg.com/Product/Prod [...] 6813157130

I would get a Crossfire-ready board, but it looks like all the cheaper ones drop the speeds down from 16x to 8x when you use two cards. So for Crossfire compatibility I might just have to go with the board in the first build list above. But then again, I'm not totally sure if I'll end up going Crossfire.

Anyways, swapping the 4850 for the 4870 and getting a non-Crossfire board brings the total to $875. I'd have a higher end video card but no Crossfire compatibility. The price is basically the same so that doesn't matter to me.

I need help with this. As i was reading over it I realized that I could also just go for the 4870 in the original list and still keep the price at right about $1000 and have Crossfire compatibility for future upgrades. Any recommendations on what to change, or should I just go with the first list but with a 4870 instead?

Whether you go with Crossfire or not, it's a good build. If you do go with Crossfire, your going to need to upgrade your psu. Either way it looks like you did your homework.

^ agreed, if you intend to overclock go with a P45, not a P43

Thanks for the tip about the PSU. Since the PSU and case were combined on my original list, I started looking at some different options. I am slightly confused though.. The MBoard says that it's got the ATX Form Factor, so would I need a Full Tower for this build or is a mid-tower fine (even mid-tower cases say they are compatible with ATX mboards)? And as far as what case size to get, I was also wondering if a future Crossfire upgrade would even be possible to fit into a mid-tower case.

If mid-tower would work, I was thinking about the Ultra Aluminus, no PSU, $70:
http://www.tigerdirect.com/applica [...] u=ULT31824

It seems like full-tower might be the way to go as far as better cooling, so I could get the full-tower aluminus for $105:
http://www.buy.com/retail/product. [...] caid=17902

And then I would need a recommendation on a PSU that would work with two 4870s in Crossfire. And sorry for all the questions, but what cooling solutions would you recommend?

Definitely change the mobo to an asus, gigabyte or msi, not sure how asrock is.

What about the MSI X48C?
http://www.newegg.com/Product/Prod [...] 6813130157
$220, or I could get the open box for $165 unless that's just a dumb idea.

And would I still be able to have Crossfire cards both running at 16x, or would it drop to 8x?

EDIT: Nevermind about the MSI X48C. I think I'll likely just go with the Asrock X48. I've gone through some reviews online and heard only good things. And while they apparently used to make cheaper-quality boards, this is actually made with pretty good build quality. Also, WiFi is a must, and not having it included would add to the build price. The overclocking ability with it is also supposed to be fairly good (not extremely high-end OCing, but I don't plan on doing it too much, I just want to push my Q6600 to around 3GHz).

Any tips on what PSU to get (Crossfire-ready) or any cooling solutions? And does anyone have thoughts on the Ultra Aluminus cases, and if I would need a full tower or mid?