For whatever it's worth, I switched my Shoutcast server over from NT 4.0 Enterprise Server to a Windows 2000 Advanced Server Configuration, and I actually ended up with a better baseline and more resources available. In other words, it ran faster
The only factor that I want to bring up concerning this is that when I ran DCPromo and tested the effects that Active Directory would have on my new 2k Advanced Server install, it really put a drain on the system. My server is currently configured with DNS Server, WINS Server, DHCP Server(for my internal LAN), Shoutcast Server, ISA Server (firewall/proxy), and with websites and ftp servers for 8 domains, so my AD on top of this may have had a larger impact than it would on most. I would suggest running 2k advanced server if you have that option available to you, and just not configuring active directory on that particular server.