good interface
 

good interface to get i have around 600
to blow

what is "good"? If you don't need any features that your audio software is going to do, like compression and mixing and such, can't go wrong with the M-audio Fast Track USB.

All interfaces are 'direct boxes', meaning that the sound in/out is completely transparent, so each is just as good as the next, just a matter of features you want.

^ the best 600 can buy
wit pro tools that is

All interfaces are created equal. You'd have to say what the "best" is because it's all about features at that point. Softwarre can do a lot of what the hardware is doing, so only you know for sure what you'll need and there fore, what is "best".