gtasks
quick office (not in market and if you don't have it, you can find it around on the internets)
*offiviewer if you need to do .docx gets converted then sent back to the phone... works pretty good.
linda file manager
gopayment- turns your phone into a moble POS (point of sale)
What type of business are you talking about? Might help a little
Evernotes is good to take and keep notes. It syncs on their web site, accessible through your PC. You can take audio notes, attach images and photos, etc. It's pretty deep and thorough and free.