Not to derail the thread into what audio interface is better, but the Echo Indigo I/O only has a single unbalanced input and a single unbalanced output. If you don't mind unbalanced, and you have a Firewire port available, the M-Audio Firewire Audiophile costs $125.00 minimum advertised price from a real dealer, sports MIDI I/O, 4 analog inputs, 6 analog outputs @ 96KHz/24 bit.
Just got mine yesterday in the mail. Oh my lands, does it rock.
Of course, there's the size factor to consider. The Indigo I/O is a PCMCIA card. The Firewire Audiophile is a brick about half the size of an external dvd burner. However, there *are* other good, cheap "prosumer" options out there for you.