BA Flights has been useful, as i sometimes travel back to the UK using BA, i can easily find my flights and check if they are late.Hopefully they will revise this to allow easy online checkin at some point.
I love a good weather app but there are not many to write home about at the moment. Weatherbug seems to only work in F and not C, hopefully they will update that too.
LastFM is also a clever little tool, works best and cheapest with wifi of course. You need to sign up but it is free and works out what kind of music you like and streams that to you.
doesn't look like it - probably because of copyright issues.
Tuner doesn't quite do the same but it works well for radio streaming. I used it for a while until Bluewin TV started offering internet radio stations via the STB
WhitePages (free) is great for finding telephone numbers, addresses and names in the USA. It also does reverse phone (If you have an unknown number on your phone you can find out who it is and show on maps where they live.