I'm fully aware that this is probably the 537th thread on this topic, but I'm only starting this so I can give you my opinion on what I think is the most underrated albums.
Phantomsmasher - Phantomsmasher
I've had this album for nigh on 5 years, and not once has it failed to shred my mind to pieces. Very intelligent ambient influenced grind perhaps? I'm not sure, but it's a bloody good record, and I think you should all get a copy. Your turn.