Zite is a fantastic iPad app for aggregated, personalized articles. Snapseed is a perfect all-in-one photo editing app for the iPad. I could go on :)

Tagxedo - like wordle on steroids!

Animoto - easy movie creation tool

Lino - like wallwisher but doesn't crash

I love using scribd for embedding pdfs and other docs.

I also love VOKI. Kids love creating talking avatars.

I love Little Bird Tales

www.goanimate.com
- create great animations

Twitter, TweetDeck, Facebook, MyPad (both Twitter and Facebook feeds). Slide and DropBox.

Aviary...photo fun in Firefox and Chrome extensions.

Nothing like a good ol' wiki (pbworks or wikispaces) for bang for your buck!