One thing to be cautious of is that Hitchens teaches you polemics, i.e. really forceful rhetoric. This can be put in the service of anything, and sweep along everyone including the speaker. That he believed everything he said does not make this stuff not dangerous.

If you find yourself tangling with annoying theists a lot, god is not Great is just the source material you needed. However, its arguments are very easy to accept while forgetting to examine and kick them thoroughly. And bits of it do go off the rails IMO, e.g. the section on pigs.