Clutching at Straws is a good entry point, the live Fish era is a good overview as well
I would stick with This Strange Engine for a while, they don't do big and obvious these days
it takes a while to sink in .Failing that as Mr B says Brave or the double Cd of Marbles
Marbles is fab. Would recommend you buy that and Marbles By The Sea as well. I am a zealot though!