Considering your potentially sensitive body chemistry, there's two good words to consider: mild and free.
Take a stroll down your body wash and soaps aisle and check for products that specifically say "mild" or for products that are fragrance-free, dye-free. It doesn't hurt to scan the ingredient labels either. If it's got a ton of letters and sounds like a harsh chemical, it probably is and the latest thing you want to do is irritate your sensitive skin there.
The only brand that comes to mind for me is Dove. It's made with more moisturizing agents than your traditional soap.
Honestly though, take some time to scout online for some friendlier feminine products. If you've got the budget for it, I have a friend online who sells [link=http://www.hysterix.org]purely organic soaps[/link]. She might have a recommendation for you, too.