Here are the sound adapters we recommend:
Buy a motherboard with embedded audio. Nearly all recent motherboards have standard embedded audio. Even the basic embedded audio provided with inexpensive motherboards is sufficient for most needs. Premium motherboards include better audio chipsets that provide top-notch sound and support such features as advanced 3D positional audio and Dolby Digital 5.1. The tight integration of embedded audio makes compatibility problems and resource conflicts much less likely. If you are building or upgrading a system, there is seldom reason to use anything other than the embedded audio supplied with the motherboard.
Philips Sonic Edge 5.1. Although Creative Labs, SIIG, and others make good basic PCI sound cards, we think the Philips Sonic Edge 5.1 is the standout choice among PCI sound cards that sell for $30 or less. Sound quality is inferior to that of the Turtle Beach Santa Cruz or the Creative Labs Audigy 2, but the Sonic Edge is fine for playing DVDs, CD audio, or MP3/OGG files and for casual gaming (http://www.pcsound.philips.com/_sonic605.html).
Voyetra Turtle Beach Santa Cruz. At $70 or so, this is the best consumer-grade sound card available. It supports six-speaker surround sound, including virtual 5.1 processing that emulates full surround sound from two-channel stereo sources. It supports all major PC audio standards, including A3D, EAX, DS3D, IA3D, and Sensaura, and provides DOS game compatibility under Windows 9X. Good drivers are available for all major operating systems, including Linux. We have experienced no compatibility problems with Intel, VIA, ALi, or SiS chipsets, which is more than we can say for some sound cards. Unless you work with PC audio for a living, the Santa Cruz is probably all the sound card you'll ever need. This is the sound card we install when features and sound quality matter (http://www.turtlebeach.com/site/products/santacruz/).
None. ISA sound cards have always been trouble-prone, and are now obsolete. If a system has only ISA slots available, it's time to replace the motherboard. The embedded PCI audio on even inexpensive motherboards is a far superior solution.
For updated recommendations, visit: http://www.hardwareguys.com/picks/soundcard.html.