Will have less than 24 hours in Philly, what should I do / see?

Will be going on a short vacation, and the last day of the trip will be spent in Philly (near Market and 2nd Sts.). I’ll be getting there around dinner time and leaving around 11AM the following morning.

What’s the best way to enjoy less than 24 hours in Center City Philadelphia?

(Note: I’m an Easterner semi-familiar with Philly, but it has been a few years since I had some time to trek about the city. My tastes are: historic stuff, natural beauty, coffeehouses, eclectic quirky, water front, blue jeans, spikey dykey / not uptown chic, cheese steaks, the occasional cocktail and cigar, Mike’s hard lemonade / not beer, etc. etc.)