Also, a more effective way of stockpiling filled soul gems is to fast-travel to Winterhold College and enter the door on the right-hand side of the courtyard. Around 2-4AM there's typically 4 mage merchants/trainers sleeping in their beds, along with an Enchanting Apparatus on the second floor of the quarters. You can generally purchase around 10-15 soul gems in one go depending on what they're selling, ideally common/lesser/petty.
Here is what I did:
1. Wait until around 2-3AM for the mage merchants to all sleep (to get them all in the same area).
2. Purchase every filled common/lesser/petty soul gem from them.
2a) If you have any enchanted daggers on you at the time of purchasing soul gems from them, go ahead and sell them to them now.
3. Go to the enchanting table on the second floor and enchant your daggers.
3a) If the merchants still have gold to barter with after enchanting, go ahead and sell them more of your daggers.
4. Wait 48hrs, then rinse and repeat, selling your daggers as you restock their bartering gold and purchasing soul gems.
note: it's best to do the above steps with a large cache of normal daggers, so you don't have to keep traveling between cities to re-smith more daggers.
Last edited by Kraderic; 11-23-2011 at 12:19 AM.