What items, arms, and armor do folks usually craft, and at what levels? I've done a little bit of crafting (taking a masterwork composite bow up to a +1, making the Helm of Read Magic, and a few other minor things like cloaks of resist +1), but my concern is doing so much that my wizard and cleric are way behind in XP, and, of course, the cash issues.
Unless you are playing a no-crafting campaign as a challenge, I think most people dump all their extra money into crafting, since there isn't really anything else to spend lots of money. I find that with 2 crafters (usually a cleric and a wizard/sorcerer) and dumping all extra money into crafting, they both usually end up being left behind everyone else by about 1 level. This is a relatively small penalty for giving everyone top-line magic arms and armor, +5 cloaks, and +6 stat pump items where needed. Once you get to Verbobonc (after the original game ends, and the C08 stuff kicks in) there are a ton of shops where you can just buy most magic items straight up without crafting and losing XP's.
Vests of escape are relatively cheap to craft, and very useful, even for non-rogues. Tacking +1 on to any Mithril Shirts you find is also useful, as well as Darkwood and Mithril Bucklers. And don't forget Greater Bracers of Archery when you get to high enough level.
How about variables on weapons and armor? For example, I haven't found "silent moves" to be particularly useful. Mostly we just roll in, swords a-swingin' and spells a-blastin', instead of sneaking around. But how useful is spell resistance [13]? For that matter, how far do people boost their weapons and armor? All the way to +3? And do folks have preferred status effects like "Holy" or "Axiomatic" or "Keen"? Any of the damage modifiers like "Flaming" or "Cold Burst"? Basically, I'm trying to decide just how far to boost my guys' gear as I go deeper into the Temple. I'm currently running quests for the various Temple factions and will soon get to the point where I can't progress any further and have to kill...someone so that I can head to the Greater Temple. Unless, of course, I want to go into "extermination mode" and try to kill EVERYTHING evil in there. But I digress. My characters are all level 8, and my team seems pretty solid. So, I'm wondering if we'll be good without crafting the higher-end gear, particularly if it can be bought and/or looted later in the CO8 post-Temple stuff.
Some answers: since most of your foes will be evil, Holy and Axiomatic(?) are good choices, as are shock and cold. I usually have a cleric and wizard craft (3 if I have a druid) and I usually try to find the two +2 swords in the game first to lessen the XP drain. I usually go to +3 for melee weapons with just the basic shock/cold/holy damage but I'll go for more damaging effects on missile weapons (gives the wizard and sorcerer something to contribute once their spells are gone or inappropriate for the current combat). A way to sidestep the XP loss for those crafting is to wait until you get nearly to the next level before crafting anything- and then don't raise them to that level. What I mean is say all of your characters have gained enough XP to reach 10th level. Let all but the ones crafting raise and let them craft what items you need- but make sure the XP loss from crafting doesn't drop them below what they need to raise. So long as they are 9th level plus (meaning that they could be 10th level if you let them train) they will gain more XP from a given situation than the characters that are already 10th level. You can do this until the characters gain nearly enough XP to reach 11th level, train them to 10th and then continue towards 11th level. In this way they won't be too far behind everyone else.
I find the armors in the game are pretty good, the elven chainmails, certain red platemail, etc. So I concentrate my crafting on weapons, as I like to use non standard weapons, and really go all out on Wondrous Items, like Belts of Giant Strength +6 (all characters can benefit from being able to carry more loot!), and other ability score boosters. Ioun Stones for those who need secondary boosts in slots already taken (think rogue with +2 STR stone, since his belt slot is taken by Escape Vest). Cloaks of Resistance and Amulets of Natural Armor help everyone. Also have your spellcasters make wands for the Rogue with a high UMD skill. An extra fireball or Cure Serious Wounds never hurts. If you want the ability score boosters, your wizard will have to take the applicable spells on level ups, add in your good spells via commonly found scrolls as Cat's Grace, Bull Strength,, etc cannot be found until you get to Verbo.
If you're crafting neck slot items, Periapts of Wound Closure are the way to go, but you'll need an 11th level cleric. As others have said, Holy and Axiomatic are probably the most useful weapon qualities (you are, after all, hunting demons). I always sneak around to position myself for fights, so Silent Moves is on my list early on. The fact that it's cheap helps too. I don't bother with Spell Resistance until later, but it has proven its worth occasionally (I usually target spell casters first so I don't often have to make saves).
Ditto on holy and axiomatic weapons. If you have a law/good cleric you might want to split it up at first giving half the group holy and half axiomatic. You should also determine if you are going to use the uber broken sword "always hits" sword. broochs of shielding can be good on shieldless characters. circlets of persuasion can be great too for faces/ UMD characters. Generally prefer stat bonus items on my casters before melee since melee can easily be given buffs but its much harder for casters to get extra spells via being buffed.
Got it. So, timing-wise, is it likely that I'll be able to get my 6-person party up to level 11 or so, to the point where this stuff will be useful, if I'm currently working my way through the 2nd dungeon floor of the Temple? I'm at the point where I've got Water, Air, and Earth working against each other, and have had two guys ask me to kill Belsornig. I've yet to approach the Fire Temple guys, but I plan to do that, too. I'm also trying to decide whether it's worth it to upgrade gear in a piecemeal fashion. Like, crafting some Wondrous Items that can be made earlier vs. waiting until I can do the entire run of items that I'll want.
Doing it earlier is better, especially now that they've implemented XP scaling for higher level characters.