http://tinyurl.com/5oruvd
He's pretty awesome if you're in the right mood, and pretty annoying if you're not. Live, he was incredible... Venereology is pretty ace, I likes.

The records he releases on his own are like nothing else on earth - pure total NOISE, no vesitge of melody or anything you'd traditionally think of as music. Pretty fucking challenging stuff. As someone's already mentioned, you've got to be in a very particular mood for it or you'll end up with a migrane. Check out 'Pulse Demon' or 'Venerology' if this floats your boat.

Alternatively, if you don't want to abandon yourself totally to noise, check out some of his collaborations - especially with Boris. Personally I love 'sun baked snow cave' where you get the Merzbow noise but also some more traditional instrumentation and it all blends together to actually become very relaxing.

1930
merzzow
venerology
pulse demon

but i don't believe there is a 'best' release to start with and there is definitely no right or wrong answer. releases i enjoy include some of the following:

minazo vol. 2
pornoise 1kg series
rainbow electronics II
higanbana
here

also in terms of collaborations, the two john wiese collabs are particularly brutal, as well as the one with genesis p. orridge, which is quite eerie and must be heard!