Hi again,
I have to disagree about the clubs. Even if you can't backstab with quarterstaves, you get a long-reach weapon and a blunt weapon all in one. Also, you will find many +2/+3 quarterstaves. There are very few clubs in the game.
You will only use quarterstaves to fight clay golems and adamantite golems (through doorways). You can't backstab a golem, so that's not an issue.
However, I'm not convinced that you can't backstab with quarterstaves. I know that you can't backstab with non-thief weapons, like two-handed swords... I'll have to try with Jan, who can back stab and use quarterstaves.
Okay, now about skills: PICK POCKETING! and Find/Remove Traps.
Open Locks and Set Traps ought to come next, and finally Hide in Shadows and Move Silently.
Why this order? Because: If you can pick pockets well, you can steal potions and items to make up for the other deficiencies. Potions of Invisibility are better than Hide in Shadows, because you can use them in the middle of a battle and they
always work.
There are some shops where you can't simply steal, so you'll have to make lots of money before going to them. Picking pockets is your friend, again. Take all the wands you stole from Irenicus' dungeon and keep selling them and stealing them back. WIth this "technique" you can easily have over GP 100,000 before leaving the Promenade. (My favorite Prominade merchant is "Jayce". Find him on the left side of the map ... out of the way, in the shadows, and only at night.)
Find/Remove Traps before Open Locks: there are a *lot* of traps in Irenicus' dungeon. There are no containers or doors which *must* be lock-picked, though. Potions of Master Thievery will help with opening locks later in the game while there are no potions which are similarly focused on Finding Traps.
Watcher's Keep is in ToB (Throne of Bhaal), the add-on for BGII-SoA (Shadows of Amn). This add-on also has an "add-in" section called "Watcher's Keep". It appears near the bottom of the Amn world map. If you don't yet have ToB, GET IT! It's got some nice fixes and great new items, and continues the Bhaalspawn story to a satisfying conclusion.
Katanas vs. Long Swords: remember that a magic weapon's bonus is added to the backstab damage before multiplication. So a +1 long sword will do the same average backstab damage as a +0 katana. Long Swords go up to +6 damage in SoA (the Equalizer vs. some foes); Katanas only go up to +3.
Short swords are great, too, and there's a short sword +2 that gives you an extra attack. The short sword which lets you cast Mirror Image might be very helpful when fighting Beholders! The short sword which gives you Free Action (protection from hold and paralyze) is pretty sweet, too.
IMHO the Trademeet bow (Tasheron's Bow) is better than the Gessen Bow, because the Gessen Bow's missiles travel very slowly across the screen. Did some patch fix this? It's been a while since I bothered with it, due to the aforestated slooooooowness.
If you get ToB and then pick the high-level ability Use Any Item, be sure to find out of you can backstab with the Staff of the Magi
-- Nifft