Amazon Kindle app. It's not a secret that I'm very happy reading books on my mobile devices, and while this has the downside that I'm tied to the format that Amazon produce I'll live with that when I can download the same book to my iPad, iPhone and Kindle and the whole lot syncs together very nicely.
BBC News. I really like the way this app breaks up the news for me, and lets me grab top stories really quickly to find out what's happening in the world. There are plenty of news apps out there, but I find the BBC one nice and stylish.
Flipboard for the iPad. This is my favourite collation resource. It takes the stories and links from my Twitter and Facebook friends, pulls the original source into a magazine format for me and makes it so much easier and quicker to read the important stuff.
iPad Dracula. I just loved this when it came out earlier this autumn, and it's a really exciting and innovative way to present the novel, making it very interactive. A character sees their way by lamplight - a lamp is on the screen and you have to move it around in order to see the text. Sound, images and interactivity combine to make a really exciting product.
Smule Magic Piano. I am not musical, not in the slightest, and I really wish I was. However, this piano app, with lights highlighting where I'm supposed to be touching the keys lets me pretend that I can actually play at piano reasonably well. My favourite 'game/leisure' application by a mile.
Trying to choose my single app is much harder than the top five, since there's a really good case for all of them, but in the end, it's got to be the Kindle app. The WhisperSync is just too clever and too freaky for it's own good, and it draw an actual gasp from me when I saw it working properly for the first time.