As far as separate DI boxes are concerned, I recently got to play around with a Little Labs IBP box. It's almost magic. It acts as a very clean direct box, but can also reamp, and is also in my opinion the best phase alignment piece of hardware or software out today. Not only can it work wonders on aligning direct and amp signals, but it is PERFECT for multiple mics on amps, drums, guitars, or anything else that has phase issues. I used it for a session last week on a kick with 2 mics on it, and I was literally able to use the phase knob on it to dial in how much low end I wanted.