My standard set of Wild Country Rocks has served me well this year. Well, at least until the recall last month. I just started climbing trad in the spring, so take that for what it's worth. If you don't have any nuts at this point, based on my experience and the advice I was given before I started putting together my rack, standard nuts are fine. Offsets would be where you want to head when you want to double up on nuts.
As for brand, I don't think it's a huge issue. I think the most common are going to be BD. Somewhere is a thread I started a year or so ago about building a new rack (I don't remember if it's in this forum or the trad forum). Not sure where you are with putting together a rack, but it might be worth a look if you don't have much at this point- tho, as things go here, it did dive into discussions on the merits of tri-cams, truck tires and the number of lockers you should have as I recall!