London - In our previous article Smartphone Wars: Nokia N900 versus HTC HD2 versus Motorola Droid (1) , we have stacked up the most formidable iPhone challengers aka. Nokia N900, HTC HD2 and Motorola Droid against each other to find out which of them is the smartest of the smartphones.

A quick look at the specs mentioned in Smartphone Wars: Nokia N900 versus HTC HD2 versus Motorola Droid (1) reveals that Nokia N900 stands out from the rest as far as the camera is concerned. The N900 has a 5-megapixel camera (like the other two) but boasts of richer features such as Carl Zeiss optics, Tessar lens, 3x digital zoom, autofocus, dual LED flash, full-screen viewfinder and multiple capture modes.

The N900 also promises to perform "PC like" multitasking, can keep lots of applications running at the same time, and switching between tasks and accessing content is as simple as navigating through the completely customizable dashboard. However, the multitasking and dashboard customizable/ personalization feature is common in all the three smartphones.

However, there are two other features which makes Nokia N900 stand out from the rest. Firstly, the N900 offers a wide choice of communication options such as Ovi by Nokia, Skype, Google Talk, Jabber and SIP among others. Honestly, I haven't seen ANY other phone that integrates so many of these services into the native phone application.

And, secondly, the N900 features the revolutionary Maemo browser, which is Mozilla-based, can run Firefox 3.0 add-ons and can handle any webpage with ease, including the extremely Flash-heavy Webkinz page. Simply put, you can browse webpages on the N900 in full screen format and it feels almost like using a full fledged, touch optimized Firefox browser with complete HTML, Flash, Javascript and other web standard support. Believe me, websites on the N900 look the same (if only with a smaller symbols and elements) as they would look on a desktop PC with 800 pixel wide resolution display.

In fact, although Nokia has so far been adamant that it intends Maemo-based devices to complement, rather than replace, its existing Symbian smartphone offerings, industry watchers see Nokia betting more heavily on Maemo as it tries to compete with devices from Research in Motion, Palm, and (of course) Apple.

On the other hand, HTC HD2 boasts of a superior processor – the all-powerful Qualcomm 1Ghz Snapdragon processor which is used to power even netbooks. Not surprisingly, processing speed in the HD2 is faster than the other two smartphones (the N900 has a 600MHz processor while the Droid has a 550MHz processor). This is also somewhat welcome news as so many of the latest-generation Windows Mobile-based phones have just 528 MHz chips.

The HD2 is also the largest touchscreen-based smartphone in the market. In other words, things like web browsing or watching YouTube videos are, not surprisingly, more enjoyable on the HD2 than what one could expect from the N900 or the Droid (though Droid has slightly better resolution than the HD2).

Also, thanks to the large display screen of the HD2, maps are clearly visible and you can even replace a conventional GPS system with the HD2 while driving.

However, most, importantly, the HD2 is the first Windows Mobile-based device to come equipped with HTC Sense UI, which makes multitasking possible and promises to deliver "new customer experiences" through an easy-to-use interface.

HTC Sense UI, which is based on the principles: "Make it mine," "Stay Close" and "Discover the Unexpected," allows you to create your own environment, to conveniently communicate with contacts through multiple channels, while the innovative features make the difference between local phone and online disappear. HTC Sense slightly resembles the TouchFlo which we have seen on other models, but HTC Sense, which lets you create personal widgets and screens for your own personalization and is capable of multitasking, takes things just that little bit further.

As for the Droid, well, it is based on the latest version of the critically acclaimed Google Android platform that makes multitasking and web browsing a breeze.

The smartphone also boasts of more intuitive and polished user interface; speech recognition capabilities; and supports Google Voice that lets you route calls more efficiently, control who can contact you, and transcribe messages.

But the most exciting feature of the Droid, perhaps, is the Google maps app that are replete with text-to-speech features, layered with traffic data and a satellite view and comes with built-in turn-by-turn, voice-guided navigation. And the best part is that it's all free!

Now that we've pointed out the positives of the three smartphones, it does not mean that they are devoid of any niggles.

And, to find out what they are, click Smartphone Wars: Nokia N900 versus HTC HD2 versus Motorola Droid (3) .