If you're planning to overclock I suggest this GPU instead: http://www.newegg.com/Product/Product.aspx?Item=N82E16814102890
Its almost the same card, and you can overclock it to reach the Toxic's (the one you have oirginally chosen) speeds and probably higher, plus it's 30 bucks less.
The GPU you chose has 2GB of memory on it and from what I've been reading, its almost as good as a Crossfire setup so you may even opt for just a single card down the line. But where's the fun in that?
PSU: The power supply you selected should serve you well, Newegg's estimated power usage for your system is around 520W, so you have some good headroom there.
Wireless adapter: I know you're looking to cut costs but IMO a b/g wireless dongle is not the way to go, especially if you happen to play MMO's. I personally purchased a Wireless N PCI card and I couldn't be happier with it! I've never been disconnected because of signal issues.
Do you need a mouse or monitor for your setup?