We went through less than two years ago. I'm glad you're travelling PE as at least you'll be off the plane and processed quickly. There's no shopping as it's more of a "holding pen" scenario and they don't want to "lose" people in retail or eating/drinking!
We were business so had the benefit of refreshments in the transit lounge, but I'm not sure what the normal lounge offers. But as girlwithanewf says, you get fed and watered well in PE.
You don't need a visa but you do need to apply for ESTA, which is the visa waiver programme. You need to get this at least 72 hours before you travel. There will be no form filling (if you remember the old green I-94W forms for landing in the US) as this is linked to your ESTA/passport now.
If you transited via the US when you travelled out here, you may be asked when you last visited the US - the transit counts! We were nearly caught out with this when we flew into LA last year for a visit. The immigration agent asked when our last visit was and we said we'd left the US on the 17 Sept 2010. We'd actually flown to London on that day, then flew back and transited via LA on our way to NZ on the 18 Sept (long story - but it cost us about 1/3 less that way!). Our transit time still counted as a "visit" so our insistence that our last stay ended on 17 Sept nearly got us in trouble!