First off: let's eliminate the easy choices.
My first question is: Do you want an iPhone? If so, end of discussion.
If you know you want a laptop running OS X, your decision is pretty easy, buy one of the various Mac desktops or laptops, and the same applies to Apple's phones.
If you want Siri, iOS and access to the Apple App Store, then buy an iPhone 4S, because you're not going to get that anywhere else. In fact, Apple is a bit of an anomaly to me, it seems people buy an iPhone simply because they want an iPhone, not because of what it can or can't do, and for that reason I tend to rule it out.
Either you want the comparably safe, strictly controlled walled-garden and healthy ecosystem provided by Apple, or you don't. I happen to be a 'don't'.
I have nothing against Symbian, but with almost no major manufacturers using the Anna or Belle versions of the OS it makes it very difficult to go out and actually buy one of these phones, particularly if you don't fancy a Nokia. However, if you already like Symbian and aren't adverse to Nokia, there's always the Nokia 600 (pictured), 700 or 701 to check out.
Nokia is a lot better than it used to be on touchscreen phones, but Symbian is not an OS I can recommend to friends for straight-forward usability. I'm also a little hesitant to recommend an OS with an uncertain future.
BlackBerry's new BB10 (formerly BBX) platform certainly has potential, but until those first handsets start rolling off the production line in 2012, there is no way of knowing.
That's not to say the current iteration of the BlackBerry operating system has nothing to offer; quite the contrary. It was one of the first platforms to have handsets on sale supporting near-field communication (NFC) technology — something still not offered on iOS or Windows Phone — and RIM has clearly tried to bring it more in line with its touchscreen-focused counterparts.
Despite these improvements, it stills feels to me like an OS rooted in the past. A platform that has had bits added onto it to bring it up to date, but not designed from the bottom-up as a modern smartphone operating system.
All of which leaves two mobile OSes in the running for me: Android and Windows Phone Mango.
I'm only looking at the Gingerbread version of Android as the majority of handsets that you can buy today are still running Gingerbread (2.3), or lower, builds of the OS. This isn't a definitive Android-versus-Windows-Phone comparison, but hopefully it'll give you some idea of what each is like to live with day in, day out.
I've been using Android daily for around two years and have found it to be relatively trouble free. It arrived doing most of what I wanted and has had more features added over time.
One of the things I find most valuable about having an Android phone are the excellent Google Maps features. I almost never need to look at a map before rushing out of the office to a meeting, and there's little need left for my in-car TomTom unit. Being a London-dweller I find the public transport information on Android invaluable too.
Windows Phone on the other hand has Bing Maps, which offers pedestrian and driving directions in a similar way to Google Maps but lacks the turn-by-turn voice guidance and public transport info.
The Nokia Lumia 800 redresses this somewhat by using Nokia Maps and Nokia Drive (pictured) which offer these missing features, but I still favour the usability and familiarity of Google Maps and Navigation.
I'm a user that prefers to have the options there, even if takes trawling through a few menus to get to the one I want to change. On Windows Phone, I sometimes feel like it is a little oversimplified or shows its immaturity. Why, for example, is there no app management option in the settings menu? If you want to uninstall multiple apps, you need to manually go through and uninstall them from the main menu, and why do I need to go to multiple places to check social-networking updates?
Ultimately, if you're tech-savvy and love to get your hands dirty, or at least have the option to without much fuss, Android probably provides the best fit right now. On the other hand, Windows has come along in leaps and bounds since its first Windows Phone incarnation — the Mango update really did bring it into contention — and is now as easy and feature rich to use as other options on the market. It also comes with the bonus of integrating other Microsoft services, such as Office 365 and SkyDrive storage.
In many ways, Windows Phone offers a similar proposition to iOS, but with the added bonus of allowing manufacturers to differentiate the experience through hardware configurations, albeit with some constraints.
On Android side, meanwhile, there is Ice Cream Sandwich (ICS) to consider. ICS aims to unify the tablet and smartphone variants of Android and brings a range of new features. ICS was released in October on the Samsung Galaxy Nexus, but is now rolling out to older handsets.
Anyway, my contract has expired and I'm overdue a phone upgrade, anyone have any ideas?
Get the latest technology news and analysis, blogs and reviews delivered directly to your inbox with ZDNet UK's newsletters.