It's a four person group, and in accordance with my "I hate low level games" policy, begins at level 5. They voted on actually having the plot be fairly traditional - they all meet, possibly in a tavern, and notice that they're all PCs. They then go on a few adventures/quests, doing cool things, and then an actual plot emerges during one of these. From there it escalates until there is a climatic battle between good, evil and the other guys.
I have encouraged them to read the Tome stuff, but I don't yet know what they'll be choosing.
So, in my grand tradition of getting other people to do the work for me

I'm tempted to, later on, send them on the greatest beer quest ever. Something along the lines of "We need more Ale. Specifically, this stuff brewed in the fifth layer of Hell. Here's the address."
Or perhaps, does anyone have a specific monster that they love to see used? I'm sure I could base a good adventure off a monster or two.