I did internet searches, I read blogs and articles... I think I spent about a day all told... although I did manage to fill six screens with Apps!
So, for what it's worth, here are my top Apps (this week, anyway).
Tube Status - invaluable if you are a London commuter. It tells you which bits of the Underground are (and aren't) working... and updates with a shake! Cost - free.
Tweetie 2 - for Twitter addicts... a beautiful clean and easy to use interface easy to use and read. Cost - £1.79.
Metro UK - get your daily newspaper fix without getting newsprint fingers. You can download the edition to read offline in the Tube. Cost - free.
Gorilacam - this adds a lot of missing functionaity to the iPhone's very basic camera... including anti-shake and zoom. Cost - free.
ContactsPlus - gives a more comprehensive and photo based interfaced to the iPhone contacts directory. Cost - £0.59 (free 'lite' version available).
Pocket Informant - a calendar/organiser application. This synchs with Google Calendars (which you can in turn synch with Outlook) giving you a total solution. The interface is much improved on the iPhone's native calendar... more like a Blackberry. Cost - £5.99 (free 'lite' version available).
101Classics - get around to reading War and Peace at last (yes, really!) and a hundred other books. Cost - free.
Tap Tap Revenge 3 - I think it is like Guitar Hero (or similar) tap the screen when coloured blobs hit whilst music plays. Dangerously addictive. Cost - free.
Facebook - take the important parts of Facebook with you - easier to read than in the web browser. Cost - free.
Shazam - wonder what that song playing on the TV is? Shazam will tell you just like that. Was surprised to find out how well it works! Cost - free.