I just recently purchased a G4 powerbook with superdrive.
I want to purchase Logic Platinum 6 and use it to record and sequence live tracks as well as some midi stuff. I will be using a Yamaha AW4416, Korg Triton, and live instruments and mics with the powerbook. Does anyone have a good suggestion for an affordable, yet professionally minded soundcard?

Danke.

I can see that you have bought nothing but high quality equipment. It would be a shame not to do the same with an audio interface. Your best bet, if you don't need more than 2 mics recording simultaneously would be a MotU 828 Mk II. If you need more they have several great options to choose from. I use two 828's with my setup, running everything into the inputs, thus not needing an external hardware mixer. Check out your options on the MotU web page under audio interfaces. They also have great midi interfaces too. Also, I have been using Digital Performer since it came out and Performer way before that. I would heartily recommend it over Logic Platinum.

Digidesign's MBox will allow you to use Pro Tools (along with Logic, DP, Cubase, etc.) whereas none of the non-Digidesign interfaces will allow you to use Pro Tools ever. I'd get the MBox. $450, 2 Focusrite mic pres, S/PDIF I/O, 24 bit/48K, Pro Tools LE software, pre-converter balanced insert for outboard gear, portable for laptop use, and latency-free monitoring. Can't go wrong with that value, considering that the software alone for Logic, Cubase, or DP are at least as much money, and don't come with hardware.

$0.02,
Jeff