Stu at Prolost has a great article on pimping out After Effects, what settings he uses, and some must have scripts.
On the scripts, BG Renderer is a must, at $29.99 it allows you to not only render in the background, but also to e-mail you when a render is done, so you can walk way, and know right when it is ready continue.
And of course Stu’s own DV Rebel Tools are also another must have.