Following up on the post I did for the Nokia N95, I thought I'd do one up for my iPhone. These would work on the 2G and 3G handsets, too. Of course, this list is subjective, but I thought I'd share.
Please be sure to let me know if any application I've listed has been surpassed by a competitor doing the same job, but better. All of this apps can be found simply by searching the name on your handset or iTunes.Reeder
The ultimate Google Reader app, better than Byline. Catch the latest from all of your favourite websites on the go, and share them with your Google contacts. You can even mark comments on shared posts and tell it to cache images and/or webpages linked to from stories.
Beejive IM
Connect to your AIM, GTalk, ICQ, Jabber, MSN, Myspace IM, Yahoo or Facebook IM accounts. Individually, or all at once. And you can continue recieving messages even after you close the application, with a disconnect period you can specify.
Consume
Check all of your monthly usage meters via this one handy app, better than Quota.
Go Brisbane
Better than "Metro Bris", but you won't be unhappy with either "Metro" or "Go" for your city's public transport companion. Search for your city specific version to get what is undoubtably the best public transport schedule information tool available. Timetables, train maps and even the ability to use your GPS and tell you what your closest station is!
WunderRadio
Find radio stations by GPS, or search the plethora of net radio stations on the world wide web, and then stream them via the internet on your iPhone. Fantastic listening to live radio commentary of an anticipated football match, or just listening to some fresh music that isn't in your collection.
Urbanspoon
Only recently adding support for Australia, Urbanspoon is quickly growing to become to resource to look at to get opinions on restaurants around the country. Search by GPS, cuisine or price - and the add a review via your iPhone once you've eaten there.
IceTV
Check what's on the box tonight, have it show recomendations based on what your favourites are, and even schedule recordings for your HTPC remotely. One of my favourite features is checking program popularity to see what's currently hot.
Foxtel Guide
Awesome for those who use Foxtel, as you can not only check the Foxtel guide, but schedule remote recordings on your IQ2 box. If you have a cable server, meaning you get all FTA channels, you don't even need to use IceTV to find out what's on FTA HD channels.
Shazam
No idea what that song is blasting through the speakers at your local or in the car on the way home? Fire-up Shazam and let it do the searching for you. You can then download that song straight from iTunes to your iPhone.
Corkbin
Take photos of your just opened wine, leave some notes for your own record, and even publish it to various social network sites to recommend to your friends.
Additionally, here are some that you should all already know about and have:Ebay
Perfect for regular Ebay buyers and sellers.
Skype
Recieve and make calls from your Skype account when connected to any Wi-Fi network.
Facebook
There's little that can't be done on the app that can in a fully fledged web browser experience - including uploading and tagging photos.
Paypal
Send and recieve your money from your mobile.