I'm not usually a fan of checking out the red carpet, but I do tend to look for what Brad Pitt Suits are shown. Between him and George Clooney, they do a good job of showing swagger. Their wares may be a little expensive, but it can definitely give you some good ideas.
Getting the look right can be tough. Obviously, everything he'll wear, especially at an awards night, is going to be custom fitted. He also has a well-proportioned body, so he can fit well into a variety of suits.
For the most part, they are the classic 2 button, single breasted suits. Occasionally you'll see him in a tuxedo, or a dinner jacket, but most of the time its a basic suit, although sometimes it is a three piece. He does tend to go for the no-tie look quite a bit too. One thing that gives him a bit of swagger is the shades, scarf, or pocket square. Many of these are made by J.Lindeberg, so keep an eye on that company. Further proof that a little accessorizing can work well!
As far as brands, I've noticed that he seems to trend toward Armani, Gucci, and surprisingly, Louis Vuitton. Versace and Tom Ford have also worked with him as well. The Louis Vuitton surprised me, as I always thought of them as more of a women's brand. While these are expensive brands, even off the rack, discounted versions can be available.
One trend you'll see is that the lighter color suits tend to work with him. This is due to his tanned complexion, which you need to have if you're in Cannes, Miami, or LA. Not all guys can pull this off, so be careful before jumping into a tan or khaki suit.