Last year's killer app for me, without a doubt was Spotify. Especially once I got my Android phone and could take it with me. What I think Spotify got completely right was their delivery of the entire package. It was immediately obvious what the app was for, how to use it and why it was better than the alternatives.
Now, while I love my Android phone, at the moment I don't use much on a regular basis apart from the standard phone, email, Internet browsing and Spotify. What I fully expect is that this year there will be another killer app that I will be using on a more than ad-hoc basis. So I got to thinking where I think this app will sit.....
For me, it's got to be education, specifically around game-playing education. I'm always looking There are some good web-based learning apps out there, but there's still nothing for me for the mobile (at least on Android!) to fill this gap. There are vocab tests etc, but no complete app that really allows people to learn properly. This is a surprise for me and I expect this to be an area that develops in a big way.
Fred Wilson thinks that gaming is going to be a big growth area too. I'm not going to argue with Fred (he's far too clever!), but for me, gaming is just not a massive hole on my mobile phone. I play a couple of small apps - Sudoku, etc. but I don't feel the need to play socially (never got into that on Facebook). I can imagine this could be a massive area this year, but it won't be on my phone!
Finally, I think Finance is the big growth area. NatWest have released an iPhone app, and I expect other banks to follow suit. Once I can do banking from my phone, all I need is some sort of eWallet and I'm a happy bunny :-)
What I'm really hoping for though, is for a completely left-field app to come along that knocks my socks off and that I never knew I needed!