Been a while since this thread was updated, but I think there's potential for more interesting conversation on this topic, so bumping/reviving with some favourite apps. Hoping other android phone users will do the same.
sweet home wifi (awesome)
- phone detects home wifi network and switches across from 3/4g ... waits for charger to be inserted, and once inserted uploads all photos from both devices to PC via local wifi network. I was using manual sync but this is so much easier. Pretty much every second day (when I plug it in) it uploads everythying from my and my wife's handsets. Very handy.
PCI database
- really useful to have DEV and VEN info on a separate device. A quick and easy reference for finding drivers
GO launcher EX
- My Samsung Galaxy (first series) doesnt have the eye candy HTC provide on my wife's new Incredible S. This app gives lots more nice stuff to look at. Heaps of options and features.
DESKSMS (awesome)
I freaking LOVE this app. Basically when Im in the office ALL my SMS contacts go through Gtalk (fits on same page as GMAIL interface or standalone desktop app). Whats the advantage?
1. keeps a record of ALL SMS correspondence with clients in gmail cloud
2. allows me to use a REAL KEYBOARD instead of the stupid keyboard on the android (im a mobile phone typing retard - you can probably tell)

from a productivity standpoint this saves me heaps of time every day.
SWIFTKEY
My Galaxy S came with a really lame keyboard, and because of my typing limitations, adding this made a whole world of difference to my pitiful ability to send messages. One of its really cool features is that it 'learns' messages you commonly type, so you can do them with just a few key presses instead of typing everything else. (from what I have seen a lot of other Android devices come with a decent keyboard at the outset, so maybe the need to upgrade is just with some handsets?)
Thats it for now. Hoping others might chip in.
Whats your current favourite "cant live without" app on your android phone?