(Lyn, this isn't a response to you. It's for other's who are still learning and eager for any additional info. I'm pretty sure you know what you are doing and you are just interested in a new technique. Use E's answer as a rule for the question you asked.)
I prefer to brine the dark meat and do a buttermilk bath for white meat. Dark meat, while being a more moist cut, doesn't need any (or very little time in) buttermilk and while the brine does hold in additional juices, brine will also impart some flavor as well and is a great medium for adding flavors as with herbs as E suggests (I like fresh rosemary).
With the white meat I prefer a buttermilk soak because it not only serves up a little less firm, it tastes as well as feels more "creamy". I realize that creamy is probably not something some are used to reading about chicken, but trust me this is a great cooking technique; think of a chicken casserole. You can also always add additional salt to a buttermilk marinade. I'd save any herbs for cooking after you rinse the buttermilk off (unless doing fried, then the choice is yours to rinse or not, but I would).
As you can tell by E's post, poultry doesn't need the same marinade time as beef or other red meats and most seafood can be done in even 10-30 minutes. A buttermilk soak for chicken can be done in 45min. or even 30 if you are rushed. And, you will not drown the bird if you go for 1+ hours or more.
As with all techniques of marinating poultry, do it in the fridge! If you are going to do the buttermilk, I'd definately rinse first if you are going to allow the chicken to come up to room temp to shorten cook time.