Need help picking bike for 5'1" city rider

I live in NYC and want to get a bike to ride with my kids in the park and also to go on tours.. I have not bought a bike ever and my last ride was a 70's Motobecane 10-speed that I rode as a bike messenger for several months decades ago. My budget is fairly low-under $600 and I am currently interested in either one of the Cannondale feminine 7's and a Specialized Ariel. I tried out a Trek Navigator and a Raleigh ? but didn't think either would be great. I am 5"1 and have achy shoulders.

Thanks so much for any feedback!

Have you looked at any Kona bikes?

Many within your price range, and their quality is quite good. You can find some pretty nice bikes outside the "Big" bike brands.

ETA: http://www.konaworld.com/bikes.cfm (scroll down to the bottom for the "asphalt" bikes) I've been very happy with my Kona Dew and Kona Smoke.

Thanks. I have not looked at any Kona bikes but will.