Hardware recommendation: what hardware to buy for my new FreeBSD desktop?

[DrJ]

should I worry about the [memory] brand

No. Compatibility issues come about once in a while, but not that often. And memory either works, and will continue to work, or it doesn't. If it doesn't work, just return it.

I've used memory from a dozen different vendors or more over the years, and all have worked just fine. In fact, I used Kingston memory to expand the capacity of a Sun workstation in the early 1990s, so they are one of the oldest vendors in the area.

You should be aware to the memory timing and voltage requirements. Brand is much less important, unless you are doing really crazy overclocking (which I wouldn't recommend).