Status update: Facebook now has more users than the combined population of 150 of the world's countries. Whether you're 'liking' your friend's cat's new trilby, playing FarmVille at work or simply sharing double rainbow mash-ups, there's no reason to leave Facebook behind when you walk out the door.

To be fair, making a mobile today that couldn't access Facebook would be like making a car that couldn't use the fast lane. Almost every handset on the market has a widget, app or browser to feed your Facebook habit. However, while the best will whisk you to network nirvana, the worst can leave you chugging along the social hard shoulder.

Unsurprisingly, some of the most impressive Facebook phones are also the highest-powered smart phones. Apps for Android, Apple and BlackBerry devices let you do almost everything you can do on the Facebook website, except play games. It's easy to upload images, stalk -- sorry, check -- friends' walls, look up contact details, send messages and start a chat. 

Apple and BlackBerry phones are particularly handy for Facebook fans as they send out push notifications -- alerts that flash up instantly on the screen when friends comment on your links or send you a message. A few other handsets can do the same, and the ability is likely to become much more common, especially after someone sets up a Facebook group called 'Push notifications for phones now!!!!!!!' Yes, with seven exclamation marks.

Many non-smart phones, even some of the very cheapest handsets, have made Facebook a central feature, with a home-screen widget that shows live updates and messages. These are great to use for now, but don't expect them to get updated with new features as often as real apps, if ever.

To get the most from Facebook, you'll want a screen that's large, colourful and sharp enough to view text, images and video clips. A slide-out or Qwerty keypad might help you type faster, although the latest capacitive touchscreens are almost as good.

Most importantly, you'll want a generous or unlimited data plan. An app or widget constantly checking Facebook might not use much data for each message, but 24 hours of updates can really add up, especially if you click on external links.

Facebook is all about sharing your life, and for lots of us that means photos and home movies. Look for a camera with a 3-megapixel or higher resolution, autofocus to keep your snaps sharp and preferably an LED flash so night-time shots don't look like a grainy 1920s coal-mining documentary.

On the video side, smaller clips (QVGA or VGA) are actually better than the sparkliest high-definition footage, if only because they upload so much faster. The best Facebook phones let you upload media straight from the camera application, sometimes with a single touch of a button.

Below are a few of the best Facebook phones on the market now, all of which have been picked out by CNET UK's very own Facebook phone gurus.