Last.fm - Since it lets you skip past more than 6 songs unlike other radios. It also has a lowfi and hifi mode depending on your network, and the app is light and quick.
FlashApp - Lets you use the flash as a flashlight.
Tasks - can be found in the "get more widgets" section of your widgets.
Dolphin Browser HD - Although it still can't save photos it's still the most fully functional of all the browsers. It seems to handle more website content than the stock browser. Although, I prefer the stock browser when accessing sites like Youtube and Picassa on a 3G connection.
Dolphin HD is a bit cumbersome, but once you set it up correctly it's a decent alternative. Just hide the stupid gesture button, check full screen, the set your homepage to google.
Opera Mini - It can save photos and is a decent alternative.
To be honest many times I end up going back to stock browser until I come across websites that don't work, then I go to Dolphin.
In the end all three browsers are lacking, but we get FireFox soon.
Where - Since it finds movies, gas, restaurants, and everything else with voice search all in one app. No need for apps like Flixter.
AndroZip - Archive and Extract many different types and it functions as a File Explorer with many functions like Copy, Move, Open, Delete, etc. No need for a separate archiver and explorer.
Tikl - I haven't used it much but it's a fantastic app.
eBuddy - Seems OK as a multi-chat client, but I really haven't tried many others to know how this one holds against them. It may suck compared to others I really don't know yet.
Zedge - And there are other apps that serve a similar function, but I just ended up recommending this to my girl since it has ring-tones and also has screen-savers.
Easy Tether It's just like PDANet, but only $10.00 for the full version. I'll just wait on Froyo myself.Most other stuff is already on the phone, twitter, face book, etc, (I use the full page alternate Friend Stream) although face book has a known sync issue I'm sure it will be fixed soon. I also like the Date Clock Widget on the phone that not only shows a neat animation depending on the weather but allows quick access to your clock, timer, alarms, and forecast.