US Perm Resident moving back to the UK

So I'm looking into this whole tax thing and getting a headache.  For my wife it makes sense for the time being, although I love how the individual states try to keep their hooks in you no matter what.

Since I'm a permanent resident with SSN and all that, when I move back to the UK, do I still have to file, now saying that, I know that my wife will still have to file, and since we are married we in theory could file jointly, but might be more beneficial if we didn't.  So, once I live, am I still obligated to file in the US, I understand maybe for the first year, since I'm sure I'll have had part residency in the US during that time, but subsequently do I.

Any thoughts on this?
Thanks

As a green card holder you are required to file US income tax returns and information returns for ever until you abandon the green card.

Ok, that makes sense and I'm not surprised by that, government gotta get their funds somehow.