But I have no idea what. Suggestions?

I'm not that big on phones, I currenty have an iPhone 3GS (which I got for free off my dad, when he upgraded). I usually stick to pay-as-you-go, but that's ridiculously expensive in Hong Kong. Contract + discount from trading in phone + lower phone prices have all lead me to decide to purchase a 12 month contract.

So, when considering suggestions, don't bother going for something ridiculously over-the-top. I don't play mobile games, and I have relatively small hands, so larger screens are uncomfortable.

Since having this phone, I've spent maybe a tenner on apps, so I don't care about losing them if I switch to another operating system.

I have no preference over operating systems, as long as the phone is stable, and it provides basic apps (Facebook, Youtube, some kind of map app, etc.). The quality of the Facebook app/web browser is quite important, and I am somewhat disappponted in the iOS Facebook app and safari app (though, they could be the best out there, I just don't know).

4G contracts are fairly cheap out here, so I wouldn't mind if the phone had that sort of connectivity.

Anyway, phone-heads and fanboys, throw out your suggestions!

iPhone 5

What did you get in the end? I recommend you just to go to a shop and get a feel of the phones.

I'm also looking for a small phone that I can use with just the thumb... don't want moblets. Still deciding between the Sony Xperia Go (looks ok, feels a bit cheap but good specs) and HTC Desire C (looks good, feels good but worse specs). I was thinking on waiting on a possible mid-range WP8 that might have this form factor since top-tiers are dedicated to big ass phones.

After the fantastic advice of thr VGC community, I went for a Galaxy Nexus (white). Affordable, good specs, not massive, and likely to get good continued support from Google.

Good choice.

I bought an iPhone 4 last month for much the same reasons: wanted something that just worked, not expensive and not S2 size. Only problem I have with it is that you're not allowed to use it as USB storage.

If you're a daring consumer, try Nokia Lumia's latest phone.

Sony Experias are quite nice.

I noticed. But isn't the Galaxy Nexus big?

It's bigger than my iPhone... but it's not Note big (which, in HK, seems to be the average size of a phone).

Get a Sony Xperia T, you'll be surprised how good it is.