Then my job here is complete. :P
No, I just mean that don't use a dagger in your main hand and a sword in your off-hand.
Summarized: If you have a dagger in your MH, obviously you're going to be using a dagger build. Dagger builds are designed around mostly "burst" damage and other than Mutilate, your OH weapon isn't going to hit for shit, there's a 50% damage reduction for any OH weapon. In a dagger build, your off-hand needs to be either one of two things:
1. A fast dagger, for poison applications.
2. Nice Stats.