[Bungleau]

For a list of what spells give what enchantments, check the best tips thread. I can never remember...

As for your other questions, you can bless or enchant up to your level in bless or enchant. But the level is the combined blesses and enchants -- IOW, if you have six bless and 4 enchant, you can cast up to six things. That can be up to four enchantments, and the balance blessings. If it's a question, do the lower one first (in this case, enchant), since once you get to four blessings, you can no longer enchant.

Argh! I'm sure this is explained better in the best tips thread as well.

I usually don't worry about toughness, since you can repair anything on the fly (once you have the skill). I usually go for damage over to-hit, since by the middle of the game, you're usually hitting anyway -- hit +1 means you're more likely to hit the target.

Don't underestimate the power of the protection enchantments -- get 'em up high enough, and you can cast a meteorstorm on yourself without having to worry.