Brooks Brothers suits are often thought off as the quintessitial American brand. They been in the men's fashion business since back in 1818.
This is a line that is very popular in the board room. They are known for having a very conservative style, that will fit most normal sized guys. They use nice quality wool. Like many designers they have different lines for different levels of quality.
*346 - This is the factory outlet line. Pretty good quality, for comparable to a department store, and for less in most cases.
*Golden Fleece - A good conservative cut line. These will normally run about $700-$800 on sale. Unfortunately, not all stores carry these.
*1818 - This is their high end line. These can easily go for upwards of $1000 a piece.
As far as cuts, if you are looking for a slim then the Fitzgerald would be a good option. The Regent is not quite as trim.