The problem I have with Orbital is that they never make a full album of great tunes. The Brown Album comes close but there's still a couple of dodgy tracks. The Green album is mostly generic except for Belfast and Chime. The Blue album is utter toilet. In-Sides is their crap phase when they did 'The Saint' and 'The Box', The Alltogether is also mostly rubbish, Snivilisaton mostly plods along except for Kein Trink Wasser which is great all on its own, Middle of Nowhere is crap too. Their latest has one good track in Stringy Acid, Wonky is also a good track but CSY & Stripes do a better remix.
To me they're a best of album, and it would go something like this:
Impact USA - Brown Album
Halcyon - Radiccio EP
Lush 3-1 - Brown album
Lush 3-2 - Brown album
Belfast - Green album
Kein Trink Wasser - Snivilisation
Impact (The Earth Is Burning) - Brown album
Walk Now - Brown album
Monday - Brown album
Remind - Brown album
Frenetic - single
Wonky (Cys & Stripes Mix) - Wonky EP
Stringy Acid - Wonky
Chime - 12" Single
Halcyon (Tom Middleton Remodel) - B-side
With Underworld, I can't think of one duff album. They're all brilliant, with the exception of Underneath The Radar which doesn't count.