After Editor/Overlord Tim Danton gave it a glowing review last month I took the plunge and upgraded my aging phone to the HTC Hero – and, so far, it’s been a fantastic experience. Android is proving to be a solid OS and HTC’s TouchFLO 3D interface makes the phone more intuitive than any I’ve used before.

I’ve been particularly impressed by the Android Market, though, which has introduced me to numerous tools and widgets that have quickly become indespensable.

Take Google’s own Places Directory, which is a prime example of how apps can be used to make life easier. Using the Hero’s built-in GPS, the software notes down your location and figures out what banks, bars, restaurants, shops, attractions and transport links are in your area – and then provides you with a route to the service you’ve chosen using Google Maps, which updates in real-time. It’s already proved invaluable when wandering around unfamiliar areas of London and works extremely well – and is a superb advert for the Hero.

Another application that’s even more impressive is Layar, an augmented reality browser which also makes good use of the phone’s GPS and net connection. It may sound complex, but it’s remarkably easy to use: choose a layer – the default finds pizza restaurants within a mile, for instance – and this information is then presented geographically over a live feed from the Hero’s camera, using both the real world and a computer-generated overlay to guide you to your destination.

It doesn’t just do pizza, either: featured layers at the moment cover golf courses, tube stations and links to Wikipedia articles, and another layer will use your GPS and Twitter details to find which users are active near you. Other layers can be used to view photographs, find a hotel or see what’s playing at local cinemas. It’s a spectacular piece of software that could be used for finding dinner or for some high-tech tourism – and is a fantastic demonstration of how this sort of technology could be used in the future.

Other applications are less spectacular but still very useful: the BBC News app sits on the homescreen and provides updated feeds from every nook and cranny of Auntie’s website, and the eBuddy is a simple and well-designed IM application that means I’m always kept in touch. The Reddit Is Fun widget, meanwhile, keeps me in touch with the weird and wonderful side of the internet that the BBC, surprisingly, doesn’t cover. Other news applications, including those from the Telegraph, New York Times and Huffington Post, are never far from my homescreen either.

Of course, not all applications are perfect. Wapedia, which is high on the list of popular applications on Android’s Market, can be slow to unresponsive even with a decent web connection, and the Hero’s built-in Twitter client is normally fine – but links, whether to hashtags or other profiles, normally don’t respond until the third or fourth click. It’s not what I’d expect from a screen which has been virtually flawless elsewhere.

Many of the apps that top the Market’s popularity charts are those that are either very, very cool, like Layar, or those that are incessently practical – but occasionally something a bit quirkier turns up, too. Take the Metal Detector. I’ve no idea how it works but, somehow, it does, filling the screen with a simple meter that grows larger as metallic objects get nearer – hit the jackpot and the phone buzzes, indicating that you’ve either found a record-breaking stash of ancient currency or a few bottle caps lurking in the soil.

One of the best things about all of these applications is that they’re all absolutely free -and I’d wager that, if they were being sold on the iPhone’s app store, some of them wouldn’t be available for nothing.

The sheer variety available is also pretty impressive: while it may not boast the volume of programs available from Apple’s store, there was still more than 10,000 pieces of software available at the beginning of September, with almost two-thirds of them costing absolutely nothing.

That means that there must be some hidden gems out there – and more popular applications that you just can’t live without. These may be some of my favourites, but what are yours? Let me know in the comments section below.