It is pretty difficult to find unbiased reviews of micro apps for some reason. Here are the parts of Android that I use regularly:
- Cyanogen --not an app, but possibly the best thing you can do for your Android. I have noticed a nice speedup and have used a lot of the tools included with Cyanogen to debug things and poke around, just scratching the surface of what this makes possible.
- A task killer. I have been using Advanced Task Killer only because it is the first search result. Before installing Cyanogen I was using something else, which worked equally well. One of these apps is essential, particularly with the limited CPU and RAM on ADP1/G1. Nearly all apps are not worth running backgrounded on this phone. I kill all tasks when things are slow. The mentioned app has a nice big "kill all" button.
- Pandora -- even works pretty well on EDGE
- Maps -- best mobile mapping experience I've seen thus far -- "Navigate" and Buzz are nice additions.
- Power widget in Android 1.6+ -- quick access to power for the various radios, brightness, syncing.
- Calendar Widget -- included "desktop" widget which lists upcomming events
- Astrid todo lists with sync to web
- RoboDefense -- tower defense game- incredible waste of time :)
- Listen -- podcast receiver from google labs.
- Google Talk -- clean enough to run in background on ADP1/G1.
- Calendar -- included app with sync to web.
- Included "music" app -- could use some polish, but it works.
- Included music & search widgets
- Bluetooth -- not an app, but the bluetooth audio support blows me away. I just get in my car, and press play in any music app. All audio goes through car speakers. I use this all the time.
Obvious missing item: mail client. I used K9 for a while, but have mostly given up. The ADP1/G1 is too slow for ~2000 item IMAP. Prove me wrong.
I have some other things that are handy somtimes, but not regularly. These include Amazon, Barcode Scanner, ConnectBot, OpenTable, Paypal- nice when you forget wallet :), Pixelpipe, Voice, Twitdroid.
I've been pretty satisfied with the ADP1 in the ~1 year I've had it. It has left me more impressed than everything I've owned prior including n97 and iPhone. I look forward to ending my ATT contract this summer at which point I'll probably buy the fastest iteration of Android phone that is available.