through official means maybe, through rooting definately

 

The whole point of the Nexus line is the updates come directly from Google, so it is updated before other phones. You will get the updates.

 

No you don't need to pay for it. As on NS all upgrade rolls out directly from Google thus removing manufacturer and carrier as Nexus class will officially be ported and supported, maintained. But however that is not the only thing as you can use latest AOSP rom just within month from most high end device so it makes no different.

 

Yes that's correct. The Nexus line will get updates directly from google. Which is much sooner than any other phones will get the update.

 

Nexus S has so far received the following updates:
2.3.1
2.3.2
2.3.3

So all you need to decide is are you happy with the phones hardware specs.

 

I'm in the UK and I haven't received 2.3.3. Should I have?

 

Not yet. It can take some time for it to roll out.

 

Well google released the nexus s a year after the nexus one. So I assume they will release the next nexus phone around December. And when they do I will be there on the release date waiting in line for it.

 

Yes so long as the updates are within the year and another Nexus Device isn't released you will get all updates after the next device is released its really iffy because if you look at the Nexus 1 they still have not gotten Android 2.3 pretty much Nexus Series Phone are good update wise for 1 year when the next version arrives. Google has been stating for a while plans to slow down their updating frequency though idk when but if and when they do the update process will become a non matter.

 

What do you mean 2.3.3? They have only released 2.3.2 lately... I'm in America and Im not running 2.3.3

 

No because it hasn't even been released to mobile devices yet. Its only available to Developers right now.

 

I downloaded the Froyo update for the Nexus One a month before it was officially released. I figure if there is a developer update for the NS available, someone would have leaked it by now.

 

The update for 2.3.3 is rolling out right now. You will get it soon enough.

 

Whatever you pick, whether Samsung, Motorola, HTC... you'll face the "next" version of it being released within a year of you purchasing it.