I'm not going to lecture anyone
but this is the article that convinced me that I didn't need any task killers.I use Widgetsoid to create application icons with custom text/icons and no gray background around the text and Glass Widgets to display the time, weather, my calendar, and a bunch of different RSS feeds.
Applications that I use regularly are pretty much limited to Google Reader, Wapedia, Google Voice (replaced texting with it, it lets me check and send text messages from a computer and can email me voicemails, etc), Amazon MP3, Amazon (in general), and Urbanspoon. DroidTropes is probably the best (possibly the only?) browser for TV Tropes on android phones - the regular site is pretty much impossible to use. I use Plotron for 3D graphing. Electrodroid is helpful for looking up resistors, remembering the pin-out of various serial cables, and a number of other calculations if you do any work on circuits, are taking a physics class, or if you need to splice together various USB cables in an emergency.