Google Android’s Market is currently free, so here’s what I’ve grabbed and rate:

5 apps to impress my friends with:

• ShopSavvy – scan a bar code (e.g. scan a book or CD or a game), displays item details, links to cheapest price on the ‘net, links to maps to show you the closest shop that’s selling it. Friends go “Ooooh that’s clever!”
  
• Shazam -Hold the phone up to some music playing on the radio or a TV commercial, tells you what the song is, the artist, links to their MySpace page and mp3 downloads.
  
• Wikitude -View scenery/buildings through the camera, see data about what you’re looking at overlaid on the live image. It’s true augmented reality, like looking through the eyes of the Terminator (except without the “TERMINATE” directives).
  
• SkyMap -Point the phone at the sky and this app tells you name of the constellations, stars and celestial bodies as you look at them.
  
• Movie Finder -Use GPS to tell you what movies are showing near you, lists the show times, links to imdb.

My current most used Apps:

• aLastFM –Streams unlimited free music from Last.fm. Clean and simple UI, lets you tune to a station based on artist, tag, recommendations etc. Vastly more tracks that the similar imeem service.
  
• Locale –Sets the phone depending on where (and when) you are. You set this up once and forget about it. I have an “At Work” situation that switches the phone to vibrate and an “At home sleeping” situation that disables sound and vibrate when I’m sleeping.
  
• aTrackDog –I expect this functionality will make its way into Android proper, but for now I run this once every few days to check whether there are any updates to my installed apps.