I can’t recommend one “best” any kind of bra because they’re so specific to each woman’s needs. I found my own favorite strapless bra at a non-chain specialty lingerie shop. If you live in or near any decent-sized city, you can find one. If you’ve never shopped at one, I highly recommend them. I find VS a little overrated and extremely over-priced. I think you’ll find that at a real lingerie store the prices are about the same, but the quality is a lot higher, the bras feel “new” a lot longer, and the attendants can help you find one that fits like a dream.
@juwhite1: I’m a DD, almost an E, and I can still wear strapless bras. You just have to find a really good quality one with a lot of support (see my advice to DrasticDreamer). It’s not the most comfortable thing in the world (the band will feel really really tight), but for a special occasion, I do it.