Originally Posted by Kraderic
The best enchantment to have on your weapons is the only enchantment he didn't list: Banish. I can typically sell any iron dagger enchanted with Banish for anywhere between 1,400-1,800 gold, depending on the gender of the merchant. I can sell them for around 2,000-2,500 gold if I dual-enchant them with Absorb Health & Banish. I don't know if Paralyze/Banish would sell more, though.
It's recommended that you either invest in the merchant's business or increase their bartering price by 1,000 if you decide to sell these daggers, as most merchants most likely won't have 2,000 gold to give you for a single dagger.
I just came across Banish for the first time today, after I finished my leveling and acquiring of armor. It was expensive and from what I can tell, pretty rare (never saw it while restocking to find the others).