WaveSecure

I think it was you guys who mentioned this app a while ago. Since I installed it on my Hero, it's been invaluable. It allows you to back up all of your contact info, including call history and texts, and download them to a new handset.

In addition, the handset lockdown gives real piece of mind should the phone get stolen and the ability to see who the tea-leaf is texting and calling is a big help to police etc.

Top class app, and FREE!! We Love You Android!

Handcent SMS

Replace the built in SMS service with one that is far more useful -

Fully customisable

Customisable bubbles to view conversations

SMS & MMS integrated together

Text to Speech and voice recognition (via plugins)

Blacklists

Home Screen Widget

Just remember to turn off notifications for your default Messaging app so that you don't get two notifications

ASTRO File Manager

I really only use this app for backing-up apps to my SD card but that alone is worth the download. I've changed 'droid handsets quite a lot recently and this back-up facility has been a real time saver by allowing me to move apps from one handset to the other, without having to re-download them.

Ace!

Astrid Task Manager

Brilliant little task manager - lets you set targets as well as deadlines along with fixed or deadline-related reminders, lets you record how long you've spent on a task if need be, and can handle recurring tasks.

AppBrain

AppBrain is more than just an Android App, it is a system that uses an App, a website and a user account. It make the Google market manageable and easy to use!

Using the website gives a front-end to the Google market but goes much further. It categorises the hottest apps and lets you see other user's app lists. It hides spammy apps like soundboards or sexy asian chicks. It allows you to get recommended apps based on your current list (and the lists of others).

From the website you can then click to install an App and it will then show up in you install list on the Android application. The AppBrain app will also show all apps that have updates pending and allow you to install them one after the other.

Overall, the best view onto the Android Market via the web and the best way to update, install and keep track of your apps.

Solitaire

It's not top of the Games list in the Market for nothing. I have wasted HOOOOURS on this little blighter.

No better time-waster around. The app, not me........... ;0)

WiFi Analyzer

I found this very useful when helping others install home networks, signal strength and quality by channel made finding the best router position a doddle. And yes, Analyzer is their spelling.

Dropbox

Having all your files(be it documents, music, photos or whatnot) sync'd between all your computers, and your Android handset is incredibly useful.

http://tinyurl.com/Dr0pB0x2

PicSay

PicSay - a photo editor unique to Android. The free version supports most basic editing needs while the €3.29 (£3.00) Pro version lets you go truly berserk with more effects than you can shake a stick at including colour popping, cutout insertion, cropping and straightening. Come the day an Android phone arrives with an 8MP snapper, Xenon flash and decent optics PicSay will be even more worthwhile, as things stand it's ideal for adding a little pep to your Facebook uploads.

AndroRemote

Allows me to connect to RDP at work. Even supports VPNs

Locale

Very useful, I use it to automatically turn my phone to silent at work - or cinemas; to turn off the screen lock when I'm at home; to disable GPS, WiFi and Bluetooth when the battery is getting low and to disable the screen time out when I'm listening to music in the car.

With all the available plug ins you can do a huge variety of things based on location or phone state including sending SMSs and posting to web forms.

Twonkymedia Mobile

Effortlessly share up media on your mobile on your DLNA devices like PS3..

The latest Twonkymedia 6.0 can also aggregate all your media. Very swish.