I like an underwired tshirt bra. I find them comfortable, give a nice shape and smooth under clothes.
I like cotton or modal (?) low rise shorts for knickers.
But I find them practically impossible to buy. I've given up hope on matching sets (knickers that match bras are always nylon?) and aim for matching or contrasting colours, but other than sticking with black (which I don't wear as a general rule) am finding that really hard too.