I try to. But sometimes it's dark top and light trousers, or vice versa, so bra and pants have to fit in with that. And I do like natural coloured bras under most tops.
I try and buy well fitting bras, and would prefer a decent bra and unmatched knickers to a matching but unflattering set.
And knickers need to be discreet - no VPL, and not a thong. I love glam pants!
So usually it's a well-fitting dicreeet bra, with co-ordinating, if not matching, posh knickers.