SP2 has many fewer bugs than SP1, so there is no need to worry over that point.
There has been some kerfuffle over firewire drives/devices with SP2, but this is the vendors fault as much as it is with MS.
The main bulk of the bug fixes and enhancements in SP2 relate to 'locking down' the computer against unauthorized access (ie. hacking) through an internet connection.
This locking down can play havoc on your prearranged networking.
Simply, if your music/gigastudio computers are never connected to the internet and/or you are using Firewire devices, there is possibly no need to move to SP2.
If your Gigastudio computers DO connect to the internet (which is most unwise, IMO), you should apply SP2 and learn how to apply exceptions to the windows firewall.
I have had NO problems whatsoever with either SP1 or SP2, so in the end your choice may not matter.
Here is a summary of SP2
"Windows XP Service Pack 2 (SP2) provides enhanced security measures that will hopefully improve defences against viruses, worms and hackers, along with increased manageability and an improved experience for users. In addition to security and bug fixes, it will change many default settings to improve security, but it may also create some problems"
(taken from: http://www.softwarepatch.com/windows/xpsp2.html )