This weekend will be the British Nationals which is in the 'Unjustly' format. This format is all cards from the first 29 sets, so everything through Unnatural Selection. Not everyone will be able to make it, so let us know what you would be playing if you had the opportunity.
Personally, I am leaning towards Relativity. It isn't too hampered by not having access to the later sets, I would also think of Khan. There are some neat tools it does not have but it still works. There are also some 'older school' decks that still have some bite to them.
Those are my thoughts, what are yours?