alright, rhode island in the house...i had to register mine and insure it, i got pulled over by an undercover statey and he got out swearing at me acting like i was doing a 100 mph, but he let me go with just a threat/so ya, you do have to register and insure....
Laws vary state to state, a synopsis is posted on the web (I believe mopedarmy.com has this.) Best check with local state laws.
In MI, for example, no title is required, but registration with Secretary of State is. No helmet or insurance required. A driver's licence or special moped licence (for 15 y/o) is required.
the only thing you need in RI is a drivers licsense, insurence, and a bill of sales/it cost me $130.00 to insure mine for the year, $20.00 to register(i bought my spree for $50.00, i think the more you pay for the spree the more it cost to register)/no helmet is needed, just eye protection