In DB2, I as curious about what constitutes the 'best' party.

From examining the Spell lists, it appears that although the
Necromancer is cool, it seems more like an interesting class but not
really wroth taking.

The Sorceror and Wizard seem indispensible.

In DB1, there was a dearth of powerful melee weapons: at any moment,
there were plenty of powerful bows but only 1-2 powerful melee
weapons available. Does this hold true in DB2? If so, then
Knight/Trog/Archer seems best; if not, then Knight/Dwarf/Archer.

And what of the Thief? Is he indispensible or only 'nice to have'?
It would be a shame to fill up a melee slot with a mediocre combat
class.

Any ideas?