1. Kindle (free)
Although Apple have their own beautifully done iBooks app, Kindle remains far and away the most popular ebook platform. Amazon's Kindle reader for the iPad does exactly what you'd expect and, with deep black text on a perfectly white background, looks far more like a real book than a physical Kindle ever could.
2. BBC iPlayer (free)
The ubiquitous iPlayer lets you catch-up on BBC programmes plus watch live TV. A very nice feature is the integrated TV guide, showing what is on. Don't forget that watching video uses a lot of data, so you'll only want to use this when you have a wi-fi connection. Or if you're desperate. And rich.
3. Skype (free)
Quite simply the best implementation of Skype which is out there.
4. SkyDrive (free)
Microsoft's SkyDrive allows you to store your data on the cloud, from where you can access it from any PC or Mac. This app brings that capability to the iPad. Fully integrated with viewers for popular file formats (Word, Excel, PowerPoint, JPEG, PDF etc). You can also play MP3 files stored on your SkyDrive, giving an alternative to iTunes and iCloud.
5. FileBrowser (£2.99)
The Holy Grail. Like having Windows Explorer or Mac Finder on your iPad so you can access folders and files stored on your computers, servers, NAS drives etc. Many popular documents and media formats can be accessed. Possibly one for the enthusiast but great if you are one!
6. Google Earth (free)
Google's ever popular application for exploring the World from the comfort of your armchair. Go to places you'll never ever go and see, fly over them and explore. Great app.
7. PS Express (free)
Adobe's PhotoShop Express allows you to perform basic editing and adjustment of images on your iPad. Not really a cutdown version of PhotoShop, but very useful nevertheless.
8. 2X Client (free)
This is a RDP (Remote Desktop) client that enables you to connect to Windows file servers. If you work in IT then you want this one as it's by far and away the best implementation.
9. GarageBand (£2.99)
Apple's own acclaimed GarageBand app lets you play a wide variety of instruments. Even if you're not musically talented you'll still love this. If you are, it's like having your own recording studio... for just £2.99! Quite stunning.
10. Epic Citadel (free)
Not really a useful app as it doesn't really do anything. It's basically a showcase for a games company and consists of a 3D walkthrough through a medieval village. The graphics are absolutely stunning, making it a superb demo.