How much can you spend? I have found that a cheap bra is a cheap bra, and if it is cheap, it often LOOKS cheap. I notice this more because I don't have the kind of breasts you can just put in any old thing and walk out the door. I have lost a lot of weight and need something GOOD.
I don't like to spend a lot of money on undergarments, though. I think I would just rather spend money on clothes I can show off
I have found the best bra ever at Victoria Secret. It's supportive, and gives me an awesome shape. This is worth the 80 bucks every 6 months or so for 2. When I have to, I can get away with 1 and rotate with old ones (they are usually $38 unless they are on sale, which VS does often).
So if you can spend under $50 finding a GREAT bra that will last a while, I would go that route. For me, it's VS.