You are given the pen at DC or Marvel. You can write any single book for a year (12 issues) and you don't have to fit things in with a giant crossover.
Who would your write?
What would you do with them?
Are we talking currently established titles, or just whatever I want to do? Because my dream book would be JLI-era Booster Gold & Blue Beetle, just hanging around the DC universe and having wacky adventures ala Hawkeye right now.
Second choice: I would take Superman and carry on with the Grant Morrison Action Comics thing of the t-shirt and jeans version of the character going after crooked stockbrokers and stuff. Those first few issues were top notch stuff and so fun. Alternate idea: Do a throwback with barrel-chested Mort Weisinger Superman with coked-out continuity and crazy Silver Age plotlines and stuff.