Just one warning...
There is one skill that you cant unlearn... Summoning dolls. If you want to use summoning dolls (with their upgrade points), then let the DK learn those... you will understand later in the game why...
Skills commonly preferred:
Restoration
Alchemy
lockpick (only works if you have the latest patch 1.47 installed)
poison
convert traps (various ones available... but they all very usefull)
Identify (not only identify;s weapons and items, but also MONSTERS.. showing you resitances, making it easier to kill them)
Weapons specialties of various natures (depending what weapon you have)
Shaman magic - hammer (stuns enemy....)
etc etc etc.
