Use an iMic
As mentioned several other places in the Wiki, the iMic is the much-preferred sound device, even over internal PCI or laptop sound cards. You should be able to find them for $35 or less and there are oh so very worth it. We have no affiliation, we just know that anecdotally, it outperforms just about anything else for ATCS Monitor field monitoring. Even if you're skeptical, buy one just to compare, just in case. It's cheaper than a preamp when you want to improve performance, which can easily be a 50% improvement.... YMMV.
-- GaryHahn - 20 Mar 2009