As Raze pointed out to me on both accounts, there arent too many awesome daggers or knifes (things that can use assassin's kiss) out there, and even though Im currently using a dagger that needed level 5 identify that I swiped from the mage in the market, its use against the elite orcs and creatures tougher then those is starting to decrease and I dont feel like wasting skill points on the hope that I'll find something more useful.
I've picked up some pretty well stacked daggers in my games so far. At the moment I am running a fighter, and she is carrying a dagger as a light spare weapon (in case the main weapon breaks at a bad time). It's life and mana stealing and has deathblow(2) and I think stun and spirit damage and poison on it. Rarely have I seen such a loaded weapon. The basic problem with daggers i.m.o. is the really low basic damage - typically around 5 - 31 where you can find lots of (fast) swords and axes that have damage topping out well over 100.
Now we come to the new Wizard character I created, Raistlin. He starts with Meteor Strike, great against the skeles AND orcs in the first part,[!]snip[!] Anyway he's just demolishing everything in the catacombs with this meteor strike but Im starting to think that I need to start grabbing some other skills from other classes. I took lock pick (Oh baby how I love this skill ) from survivor, and repair from warrior... but from there I'm outta ideas. I guess augment defense would be good for him because he's not going to be strong so he wont be able to wear heavy armor, but besides that Im running a blank.
I guess you could take shield and magic shield - but I've never needed them for my mage! As I said, I am running a fighter at the moment and she has shield and magic shield and they are fantastic when you wade into a group of steel skellington warriors, sword flashing. But my first character, a mage, never needed them because nothing could get close enough to deal out much in the way of melee damage! I think you should consider getting freeze (attn: some monsters are immune!) and to circumvent magic resistances get hell spikes at as high a level as you can (kill 3 dragon riders with two castings!) Otherwise I agree with picklock and I also like alchemy at least at lvl 3 so I can make normal size potions (in case you haven't noticed: restoration potions are MUCH more effective than either of their two components alone).
And polymorph lvl2 served me well against the odd fast powerfull boss monster that I couldn't overcome easily otherwise, for instance the regenerating spirit of the sword in the rock - he's not so hard as a froggie -- <img src="/ubbthreads/images/graemlins/stupid.gif" alt="" /> -- Kermit?!? Is that you?!? Croak!
hope that gives you some ideas to try ... -Peter