Check out
Video Game Cheats - Video Game Reviews - Video Game Codes - Video Game Web Site - GameFAQs for a detailed page on everything crafting.
Crafted items can only have 3 enchantments. Therefore, its usually best to start with a clean slate.
You can have multiple elements, vs alignments, withing the limit of 3 enhancements.
You can only put up to +5 enhancement on a weapon.
Not to many specials (vampiric regeneration is one). Check gamefaqs for a full list.
What materials are good for is a good question. They are most useful for passing damage resistance. For example, Stoneskin gives 10/adamantine damage resistance, so adamantine weapons will pass this.
I would also like to know if anyone has a definitive list on what creatures have what resistances passed by what material??
Until we have a comprehensive list I'll say what I sort of remember.
Werewolfes - silver
Vampires - silver
Warlock (spell) - silver
Stoneskin - adamantine
Iron Golem - adamantine
Warlock (natural) - cold iron
Fey ?? - cold iron
Some outsiders (sucumbi? mefits? imps?) - cold iron, or darksteel
Devils and Demons - one is silver the other is cold iron