Forget the Anakees on offroad. Not good enough on gravel too.
For GS-offroad the ultimate tyres are Mezeler Karoo. Then TKC80 and then Heidenau K60.
Metzeler Karoos are the best offroad because having the most offroad-oriented knobbies, but they also have the softest materials, which giving them huge con - they last very little on driving on tarmac. But they aren't that expensive as TKCs though.
Continental TKC80 last very well for a knobby-tyre on tarmac, though they aren't that good as Karoos, but i'd say they're next to it. Con for TKCs is their high price.
Heidenau K60 is the only tyre for oilhead GS measurements, that fills the gap between knobbies (Karoo, TKC) and dual purpose [read: strict tarmac] (Tourance, Enduro 4 etc). So i think it's only the few tyres deserving the real "dual-purpose" name are TKC80s and K60s. K60 are CHEAP, but very high quality for that price. Knobbies aren't that agressive as TKCs or Karoos, but they're considerably more agressive than those "pseudo-dualpurposes" Tourances, Scorpions etc have, they are excellent on gravel and have considerably more traction on dirt than any street tyre. K60s last more than 12Kkm on my riding style that's mostly two up and not fondling my bike, front goes 15K+.
So if you plan to do mostly only offroad and gravel - Karoos are the best choice by far. If doing more tarmac, but want some bang on gravel and bit dirt, then K60s or TKC80s, depending on budget. If tarmac only then any "dual-purpose" (as we know wrong - Tourance, Scorpion, Enduro etc etc) will do it.
Hope this helps, Margus