Adobe Flash 10.3
WhatsApp
Adobe AIR 2.6
Riptide GP
OpenFeint
Where
Penultimate (Xournal is a worthy replacement)
(official) Twitter App
Logitech Squeezebox App
Planetary (iPad)
Pulse
CNN - widget alone saves me time

I could think of many more, but that's about all I'd say I'm truly missing between iOS, Android and Maemo.