1. I will be moving to Europe in a few months.
2. I have chosen the 1600 RAM because of the promo code and the instant rebate.
3. I am not sure the 400 watts PSU is sufficient to power the 4850.
4. I do not need such a large HDD. I am willing to get a smaller HDD as long as it provides the same performance.
5. I plan on adding an SSD when they become affordable.
I would appreciate your comments on that build. I am ready to reallocate the money or spend a little bit more to increase the FPS I will get when playing WoW. I understand I will not play in 1900x1200 with everything maxed out, but since I am currently playing on a single-core P4 with a RADEON 9250, I am sure this build will be a huge improvement!
For your current resolution that 4850 is fine, but I'll tell you right now for 1920x1200 you will need a meatier card. Especially considering an expansion is on the way. And one thing blizzard does well every expansion, is turn up the eyecandy and use more resources.
The 5770 will barely perform better than the 4850 but it supports DX11. The 5830 is on par with the 4890 so it will be better than the 5770 obviously. But if theres anyway you can swing it, I'd definitely try for the 5850.
I think you are right, the 4850 won't be powerful enough for high settings and high resolution, bit since my budget is limited, I'll stick with the 4850 and lower my expectations.
In a few years I will change the 4850 by another 100$ card, which could be the 5850 by that time. The mobo I have finally chosen (a Gigabyte, I don't have the link on hand) is pretty future-proof (USB 3, SATA 3), so I will be able to upgrade a few parts of the rig over the years.
One thinbg I have changed following your comments is to replace the Corsair 400 watts by an OCZ Fatality 550 watts. I feel more comfortable that way, even though I have read so many good reviews about the Corsair, and how it performs better than many 500 watts + lower quality PSUs.