At this point, I wouldn't worry about a standard Midi connection DIN plug. Anything relatively new uses USB for midi data transfer.

If you can afford it, I would recommend the Apogee DUET, especially if you plan on using Logic and Mac. Nothing will touch it in the $500 price range. There would be no excuses for anything less than pro-quality sound with this.

http://www.sweetwater.com/store/det...rabber&utm_medium=comparisonshopping

If you can't spend that much, than I would still recommend Firewire over USB any day. You'll get lower latency and a lower CPU hit. The Presonus FireBox at $250 is a pretty nice interface that will give you above-average sound quality.

On the Virtual Instruments, I have GPO and I also own EWQL Gold. East West absolutely KILLs GPO. I even think that the EWQL Silver is more lush sounding than GPO. Go to both web sites and listen to their demos and see which one you like better. Both have online demoes you can listen to. You may still prefer GPO (and I do still use the horns and some percussion from it occasionally). I just found the strings in GPO harsh compared to EastWest.

One more thing...With Logic Pro, you get the EXS24 sampler that comes with a basic set of orchestra samples (I believe they are taken from the Vienna Philharmonic Orchestra collection - very nice!). You may want to give it a try before spending the $$ on another library. If your orchestra needs are pretty basic, it may do everything you want.