From my understanding, "NVIDIA's" *support* does not include full functionality of the sound. You have to pay OSS for a decent driver.
AGP is a nightmare ...if you don't have one of THEIR video cards.
You've got to install a pre-release versioned kernel just to get the PCI ID's right for the NFORCE2.
Oh yeah... almost forgot, thanks NVIDIA for adding your pci id's to someone else's driver!
And regarding closed source drivers - Saying you don't mind closed source drivers is similar to saying you don't mind giving out your root password. A kernel driver can do anything on your system, it is usually a good thing to know exactly what that is.