I would choose Hairspray (may be easier to get tickets to), however, if you haven't seen Lion King why not see that? Maybe you'll love it. It depends on what you're looking for in a show. Hairspray is about the fun, laughter, comedy, and the dancing, while I think Lion King is more about the visuals, scenary, and costumes.
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611