My most used Apps, in no particular order. A few date back to up to 14 months ago when I first bought a G1, but all work fine on the Droid:
Home++ ( I used to use Open Home, but FC & lagged too much - this one is great)
Weather Widgets - Donate
Pure Calendar Widget
Pkt Auctions ebay
Quick Settings - toggle all settings - free, covers them all, works great.
Battery Widget - no one seems to have one for droid in increments finer than 10% - this one works fine
BuzzOff - set to silent or vibrate for set length of time, then revert back to normal setting -- a must have if you ever forget to take back off silent.
FastBright - touch to go to full screen brightness, touch again to go back to your normal setting. I use this whenever I will be going outside for awhile.
Upvise Personal - use to store personal data other than than I keep in Contacts - autosyncs to web
Finance (Google) - live quotes & link to your Google Finance acct
CalCOOLator - much better calculator than OEM
Free Ticker Calculator - saves your calcs on a ticker for easy viewing
iHeartRadio - Listen to any Clear Channel station, any format, any city