The Limited has leather (you can't get cloth in a Limited), heated seats, and power seats, which my wife needed to be able to adjust for a changing bad back pain -- and the Limited was the only way to get power seats.
Also dual zone climate control, anti-theft alarm, illuminated running boards, and auto-dimming mirror with compass (a feature I've learned to really appreciate).
And my favorite, only on the Limited -- the illuminated instrument guage needles. The way the guages are set deep down inside those cylinder housings on 4Runners makes them almost impossible to read in many lighting conditions. The Limited's illuminated dials makes them always easy to read -- great feature -- don't understand why this isn't standard..
Side airbags are optional in Limited (and all other models), not standard. The most significant safety feature since seat belts on all 4Runners is what Toyota calls Vehicle Stability Control (VSC). Generically, this is called Electronic Stability Control (ESC), and will become the most significant life-saver in single-vehicle accidents and rollovers. It's one of the main reasons I bought a Toyota SUV.
Also, the Toyota distributor will often add certain additional options to most of it's Limited models, which makes it difficult to buy one without these options. For example, Southeast Toyota Distributors (FL, GA, NC, SC, TN) usually adds the Power Moonroof and upgraded JBL stero system to Limited models.
So, in summary, the difference between the Sport and Limited is a collection of luxury items that are certainly of real value, but also items than many people can live without. But, in my few days of ownership, I can say that the 4Runner Limited is as good or better than any luxury vehicle I've ever driven.