I see they've updated their list since the Droid was first released, awesome. Here's an abridged version to help ya out:
It's been brought up a few times on here that task managers and uninstallers are unnecessary b/c the Droid already has that built in. So you'll free up some space by not needing those.
Slacker Radio is pretty cool, as is Pandora. Also check out Dizzler, iMeem i Music, Last.fm, DroidLive, and Cherry Rplayer for varying music or radio streaming apps. Another must have music app Shazam, which is just like Song ID from VCast.
Try Bloo, rather than the Facebook for Android app.
Never tried Fring, but I use Meebo IM which does the same thing. Will try it out and compare.
Handcent SMS is highly recommended.
Google Goggles will get you some attention (scanned a girl's beer at the bar, worked like a charm). After you have said attention, take them outside to show 'em how Google SkyMap works. Oh, and they're just good apps to have, lol.
Shop Savvy and Barcode Scanner are both handy tools.
Have at it. Just make sure you're monitoring your apps b/c too many running at the same time will bog down your Droid to disastrous results. Just remember: Settings > Applications > Running Services.