For a pale ale, about 10lbs of base malt (2-row), and then 1lb of something for body, like a crystal malt.
For IPAs or "bigger" brews, you can go up to 16lbs or more of base malt, plus 1-2lbs of other malts and such. There's a lot of variety out there. I'd say start looking through the recipes section of these forums and see what sorts of bills people are putting together.