Here is my list of top 5 must have iPad apps under productivity category. I use them regularly and find them very useful.
-
InstaPaper
This is a simple yet very powerful app, that allows you to save web articles to read them later and even when you are offline. Simple it sounds, but the way instapaper performs this task, the kind of options it provides for saving, managing and sharing web articles makes it an indispensable app. Starting version 4.0, the app has become more iPad friendly, making it a pleasure to read the articles on iPad. Once you create a instapaper login, you can save web articles to your account from any web browser, using the bookmarklets that instapaper provides and sync them to ipad/iphone for reading them later. You can organize content into different folders. Instapaper provides bookmarklets for each folder and you can keep your articles organized. Instapaper lets your share the articles on social networks sites like twitter/facebook. And if you want to store any articles in cloud for your reference, you may do so by sending them to your evernote account, for example. This wonderful app is more than worth every penny you spend on it and is available for download here. -
Evernote
This is one of my all time favorite apps for various reasons. Its ability to sync across different devices tops the list of reasons. I use evernote to take notes using my iphone, clip interesting web articles when I am at my windows laptop / iMac and use this iPad application to read at leisure. When ever I read articles on instapaper, if I find any interesting articles that I may want to keep it for longer, I send them to Evernote. The iPad version of evernote has still lots of room for improvement compared to PC/mac version, but its sync across devices feature make it to the top. And this app is freely downloadable from itunes here. -
iBooks
This is a free built in application from apple for reading ebooks and supports different formats. This includes iBookStore where one can buy latest best sellers as well as old classics. I use this app mostly for reading books in epub format and it is also a good PDF reader. -
Kindle
If you have a kindle account, this is a must have application for reading all your kindle books on iPad. It has got a good easy to use and easy to read interface and is optimized for iPad. It is on par with iBooks and is available for free on itunes store. I use it mostly for reading my kindle books. -
GoodReader
GoodReader is a robust pdf reader application for ipad that allows you to annotate/edit and organize PDFs and text files. It works nicely with pretty large files as well. It also acts as a file organizer for all your ebooks. I particularly like this app for its ability to sync files with external servers like sugarsync, dropbox etc. I personally use sugarsync to keep my ebooks accessible across devices and use this application to read/edit/annotate PDF files. This application is available for download from itunes here.