If you try and profit from someone else's brand, then you are opening yourself up to legal action under intellectual property law. I would advise against it, but that's not to say some people don't try it.
Generally speaking the brand is not going to like it, it's not worth the hassle in my opinion. If you were dead keen on starting a site with a domain containing someone's brand, you could ask express permission, but then that's a lot of hassle too.
Stick to high quality generic domain names - that's where the real potential is anyway.