I've been using my iPad for about a month now and Im finding it very useful for business. The big advantage for me is the boot up time. Even from hibernate my laptop takes a few minutes to get going and the keyboard on my iPhone is a little too small for typing.
Below are my 5 favorite iPad business apps
1.Evernote I've been using evernote on my PC and iPhone for about 6 months now and I love it. Simple to use. Great search function which can even search text or handwriting inside photos and of course its free.
2.iSpreadsheet Being an accountant I couldn't do without a spreadsheet app. iSpreadsheet has a pretty decent free version which I have used to edit a few spreadsheets when my laptop wasn't nearby. Apple have their own iWork numbers app which I have used and its excellent but for most light business users iSpreadsheet is fine.
3.Good Reader As well as being an excellent PDF reader GoodReader can also view Word, Excel, PNG, TXT, JPEG files. I've a few massive 500 page technical documents on Goodreader and there easy to browse and easy to read. GoodReader has a WiFi transfer option and can read files from a web-server.
4.Whiteboard Pro I use whiteboard pro for taking very quick notes or drawings and emailing them off to clients and colleagues. Theres also a pretty good free version.
5.Drop Box Is great for mobile worker. Its cloud storage solution with a 2gb free plan. Dropbox works on iPhone, iPad PC and mac Automatically syncs when new files or changes are detected.