I think that highlights are the most fun thing, ever!
Personally, I get "chunky" highlights, especially on top. They are pretty wide and not really natural looking. I think they are fun, but they do need to be touched up more often -- I get mine done every 8 weeks, but could probably go longer without looking too awful.
My natural hair color is dark blonde, but I get really blonde highlights. If you're trying to decide between chunky and more natural highlights, you may also want to consider your haircut -- I have a very simple, straight, chin length bob, so I think the color works with that -- because the cut is so simple, the color makes it more interesting without being too much. I wouldn't have chunky highlights with, say, a layered cut or hair that is very long. Also, if you do get chunky highlights, you can always make them look more subtle by messing up your hair a little.
I always get foil -- I had the cap once when my hair was super short (the stylists I go to only do the cap if your hair is too short for foil) and it HURT. I hated it, and I don't think the results are as good because the stylist can't get the color as close to the roots, in my experience.
Unfortunately, I don't have any suggestions for you in terms of color, or SF stylists. Let us know what you end up doing!!