The Nvidia brands to go for are ASUS, Gigabyte and MSI. Between these manufacturers there isn't really much difference, all perform similarly. I go for MSI personally because they tend to overbuild there cards (especially the Hawk and Lightning editions), but either of the other would be fine.
EVGA is another big manufacturer, but I avoid them due to their reference design cooling.
You could run this system on 450W. I just usually recommend a 550W supply for the extra headroom. The supply you picked is good quality, should be fine.
The amount of VRAM is only a factor when you are gaming across multiple monitors or at a large resolution. For a single 1080p screen, 2GB is plenty.