I'm looking for a USB sound card for use for music and games. I've narrowed it down to two, both of the Sound Blaster brand: X-Fi Surround 5.1 Pro and the E1. I'll only need stereo output, which is why I think I would probably be fine with the E1, except that it's an amplifier instead of a sound card. Which one would be better for my purposes? Would the X-Fi Surround 5.1 Pro be worth the extra $15-$20 for me?