Only had my Pebble Steel since Monday, but I’d say the most impressive app I’ve seen so far is the UK Transport app – with this you can quickly see the nearest location for Trains and Buses – plus next Depature Times – and also the status of all the Tube lines.
I’ve provided some more info on my first thoughts on my Pebble Steel on the TechTestLondon.com site at http://techtestlondon.com/pebble-steel-first-thoughts-best-apps-far/