Astrid:
Astrid is a simple to-do manager into which you simply start typing, add context if you want to, then save. You can create advanced filters in Astrid, sync it to your Remember the Milk account for access on the web, and, most helpfully, Astrid is an extremely tenacious beast that won't stop reminding, beeping, and buzzing you until certain very important tasks are done

Evernote:
Evernote's universal note app on Android is not as elegant, fast, or intuitive as Evernote on iPhone. But with the latest update, the app has gotten a lot more usable. There's a home screen widget for quickly searching out notes or recording new text, image, or audio notes. You can send any text, image, or audio on your phone to Evernote through the "Share" menu. And with offline caching and speed improvements, Evernote offers an impressive, seamless thoughts-into-notes experience.

TripIt:
TripIt saves you from the print-outs, email searching, and airport panic sessions common to modern-day travel. Sign up for TripIt, forward your travel itineraries along (or have TripIt automatically import them from Gmail), and then you've got a whole master travel plan on your phone—check-in links, flight information, weather and traffic stats for your destination, and so on. It's an essential for frequent fliers, hotel guests, and train travelers.

Facebook for Android:
Until this past month, it was a shame how diminished the Facebook client looked in the shadow of its successful iPhone counterpart. But now Facebook's Android presence is capable, good-looking, and even offers a few of its own unique perks, like a pull-up notifications shade and a front-page scroll of recent photos from friends.

Google Voice:
Android's tight integration with Google Voice, the service that puts your voicemail, SMS, and phone management in the cloud, is one of its key selling points. After many revisions, Google's Voice app now makes calling or SMS messaging with a Voice number nearly indistinguishable from a standard call, and the voicemail transcriptions and playback are just another nice bonus of the Google halo.

Twitter for Android:
Honestly, we could have gone one of a few ways with this recommendation, but Twitter seems like the best app for the average Twitter user. Other apps, like Seesmic and Twidroyd, offer all kinds of nitpick options, like choosing between old-school "RT" and the official retweet methods and supporting multiple accounts. But if you like clean looks, smooth transitions, and just an easy way to update your status, the official app is the way to go.

Barcode Scanner:
Until the Market updates with Google's plans to provide over-the-air, instant browser-to-phone app installation, Android enthusiasts have taken to scanning quirky barcodes, or QR codes, to quickly install an application from a blog or print magazine recommendation. To grab those QRs, you need Barcode Scanner. It also offers some basic Google search functionality, but there are better shopping apps, one covered in this list in particular.

more to go…..