[tiberius]

Since you already listed the most important contexts (I could only add specialty stores), there are some improvements to the Nearby view I'd love to see, to avoid getting shown irrelevant stuff:
1. limit distance, i.e. show only stuff in a distance of max 3 miles (or some other configurable value). I frequently get shown stuff for contexts I definitely cannot reach right now.
2. limit time (i.e. I'd like to add opening hours for stores. I live in Europe, 24/7 store availability does not exist here, not even for the biggest chains :-)
3. add Nearby to OmniFocus Mac (isn't there location-awareness in Snow Leopard?) My favorite way to have this would be a "Sort by distance" option for the sorting field in the list view. Then I could add my own Nearby perspective.

tib.