[Russ]

I agree with you, Azred. Viconia vs. Jaheira is, to me, very much an apples and oranges kind of affair... Viconia is an evil priestess, and is useful in that context. Jaheira is a multiclass tank/druid, and it is in that context, taking into account all of the things that she can do, rather than gutting her character into the efficiency of any one facet, that Jaheira becomes incredibly useful.

Further reasons, for you powergamers out there for whom the "role" in roleplaying is spelled with two l's...

Summoning: animals, elementals, woodland being for auxiliary support spells.

Combat: has been gone over. Obviously, she can't use Crom Faeyr. Duh, she's half druid. There are other goodies available. Ability to get scarily good with club or spear is a handy thing. Can also be pretty nasty with the right staves.

Spells: (not counting cleric-accessible spells, which is unfair to her, but which have also been gone over numerous times)
Entangle -- often overlooked. Doesn't disable missileers or spellcasters, but keeps tanks out at a distance where they can be conveniently filled with arrows and cloudkill.
Fire Seeds -- not Melf's, but occasionally very useful.
I find Call Lightning generally useless, except when I know I'll be outdoors, and especially outdoors with lots of opponents.
AbsoLUTELY my MVP.