Well, I finally decided to upgrade my old nForce 680i, e6700, and 8800 GTX for an MSI 790FX, Phenom 9850, and GTX 280 (when it's released in like two weeks). Along with a new copy of Vista Ultimate x64 and a 2x2 Gb kit of DDR2 1066, I'm planning on it setting me back about $1250. Honestly, Intel chips might have the performance advantage right now, but for ~$225, I'll still be getting more performance in multi-threaded apps over my old e6700. What really sold me were the specs on the GTX 280. 240 stream processors (compared to my 8800 GTX's 128), 1 Gb GDDR3 compared to 768 Mb, and 512-bit bus compared to 384-bit. Also, I'm interested to see how the PhysX chip works on the card (I'm guessing that it will support something), and I can't wait to start folding on this card as well. Phenom 9850 should provide some tangible benefits as well.

Just for now, you would still probably be better off going Intel.
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115017 Especially if you do consider overclocking.
I would also wait to see AMD's latest release, the R700, which is scheduled to release around the same time as the GT200, but I don't think it's going to match nVidia's flagship card, the GTX280, but that's supposed to cost like $600.. :\
More later, I've got to go to school.

I've read some great things about the 9850 Black Edition, and if the performance is roughly equal, I'd rather go with AMD.