Ah..yes, Atheist - A wonderful oldschool technical death metal band, and my favourite band of all time. They've released three albums:
1.Piece Of Time
And I adore all three releases. All three of them are so unique and so diverse. The common aspect is probably the technicality that surrounds all three albums. I can never pick a favourite album if I was asked to, but I hold UP a tad higher in technicality than the other two, and I slightly fancy PoT, because it was the first Atheist album I heard.