ThinkFree just released an online version of their Java office suite. It offers you a spreadsheet, a word processor and a presentation tool as applets. Not only do they look great but they are incredibly useful. Along with your account, you get 30 MB of free storage which let you show your presentations almost everywhere you go (with fullscreen mode.) They also have blogs and Flickr support.
This is an impressive example of what applets can do for the web. Go check it out, you won't regret it!