There are probably as many opinions on this topic as there are Android power users. Here's mine:
Advanced Task Killer: meh!
Better: Elixir; SystemPanel App
Better: Astrid; Best: Astrid (free) plus Astrid Power pack (paid).
DroidAnalytics: meh! mAnalytics: yuck/ugly/limited.
Google Docs: unnecessary if you have Documents to Go
Astro File Manager: meh!
Pales in comparison to: File Expert
Pales in comparison to Soundhound
Google Finance: meh!
Better: PageOnce and/or anMoney
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