To my knowlege, (and I watch this closely as an industry consultant with a rapidly growing business), Realtor.com (owned and operated by the National Assoc of Realtors) remains the only coprehensive site for 100% MLS listiings throughout the country. Sites such as trulia and zillow remain agent driven and are becoming in a force to wrecken with!
In the years to come, I personaly foresee Realtor.com being in DIRECT compeition w/ sites sich as Trulia. But for today, Realtor.com prevails (but, not for long). Go Trulia!
Love and Peace,
Francesca, Realtor, ePro