Wow is going to scream with that card. I personally have always been a huge fan of nvidia. As far as boards go, there are a lot of choices. If your only going to play wow, then you do not need to go crazy. Im partial towards the EVGA boards, such as the 780i.
http://www.newegg.com/Product/Product.aspx?Item=N82E16813188027&Tpk=780i%20ftw
Its SLI ready, just in case you decided to get a 2nd card. The OC on it is very nice. Cpu, im actually partial to the core 2 duos, but quad core is what everyone is looking at now.
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115041
can be clocked over 3.4 without any trouble. if you have even more money, you can step your processor up a bit. As far as case / cooling there are a few options.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835106102
+
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103047
one of those would work for cpu cooler. (im not sure you will need to overclock your cpu to play wow. You may not even need an aftermarket cpu cooler if you are just going to raid wow, but its an option if you decide to pimp out your pc.
I have used a lot of cases in the day, but i sware by this one.
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119137
I love it, it has many expansion slots for multiple fans. Its big, has a lot of room for heatsink and what not. Slots for 7 possible hard drives, and even more room for tons of drives. It doesnt look that great, kind of boring, but for effectiveness, it is the best imo. Case is a matter of preferance.
I almost forgot, Memory. A lot of people sware by a few different brands of ram. If your gonna overclock your computer a lot, id suggest OCZ or G Skill. If your just going to run it at stock, CORSAIR is the way to go. This depends a lot on your OS. If your gonna just run a 32 bit xp, id suggest 2-3 gb of ram. If your gonna run 64 bit, as much as your little heart desires. I suggest running 64bit vista ultimate. Rock yourself out with 4gb of Corsair Dominator.
Remember when shopping for ram you want to look at a few things. The speed of it, and the timing. Id suggest corsair dominator, it can be clocked to 1066 no prob, with a 5-5-5-15 2T timing, very fast. IF your looking for something faster, id suggest ocz or gskill. Hope this helps.