A non-exhaustive list of apps I'd like on Ubuntu.

Generic

Audio memo recorder
Podcast downloader
Comic Book Reader
WordPress client
IRC Client
Audio book listening app
Wikipedia offline syncing client
FM Radio
Business card scanner

Games

Breakout
Candy crush
Frog tap
Piano

Proprietary

AudioBoo audio recorder & player

FFOS Apps

Simple rss
Woodblox
Wikipedia
Notes
Mazeflow
Caelum
duolingo