Part of why I was drawn to RTM is the Location feature and have been disappointed by how little it's been developed. The W3C working draft on a browser geolocation API could provide the sauce for some useful location services in RTM and Google Gears, which you're already using, implements that in 4.0.

The first thing I'd like to see: ask the API which of my locations I'm nearest and offer me a view of my tasks that filters those assigned to other locations. Including tasks without a location seems a good default since many tasks are location-less, but if I've said a task is for Home, I don't want to be distracted by it at Work.