I was recently in Providence for a night and Al Forno didn't disappoint. We went late and there was no wait. Get a baked pasta and a grilled pizza to share and maybe one more thing. And dessert. Lastnightsdinner also recommended www.farmsteadinc.com and www.newriversrestaurant.com, which I'm hitting next time!

We had great Italian food at Camille's. We were there for lunch and were dressed casually. You can check their website:
http://www.camillesonthehill.com/

I went to college in Providence, and I was never super impressed by Al Forno, but I feel like I might have hit it on a bad night or two. My favorite restaurant is La Laiterie, also highly recommend their cafe (Farmstead) for lunch. I also like Hemenway's for seafood, and New Rivers downtown is really good too.

For non-fancy recommendations, I'd look at www.roadfood.com. (Just type in Providence, RI.) Jane and Michael Stern are regularly on NPR.

http://www.crazyburger.com/

A cute place on the beach. Great for lunch and satisfies all tastes - carnivore, vegan, vegetarian, gluten-free. A little out of town - but great for a day trip.

I second (or third) Al Forno and Farmstead. Also don't miss East Side Pockets for great falafel!

I second La Laiterie!