Hmmm.......Funny that you say it's just a toy, because I've had Leopard running perfectly on my AMD machine since...wow...late October, early November....
QE / CI works,
Toast works
iLife works
iWork works
CS3 works
vmware Fusion works (i have to have windows to be able to connect to my work's VPN.)
I have installed ALL updates. (just need to have Marvin's Utility handy.)
Everything I have installed works. No issues, no problems.