if you need just 2 channels, than i'd recommend a m-audio mobilepre usb. it has 2 lines in xlr or 1/4", or can do a stereo mic in, has a headphone out, two levels, and (the best part) is USB POWERED. I've been using this to record every single practice and show with some overhead mics and it does the trick with my laptop. cost $149 and has been great so-far. If you wanted to plug a guitar into one channel and a mic into the other, this does it for me.