There seems to be quite a few bugs in Safari... on the
Apple discussion forums they seem to have traced the inability to quit down to the Dock icon, but that is on Lion; don't know if it applies to Snow Leo.
For me, the "Quit Safari" button is dimmed, Cmd-Q doesn't work, and there are no close X's on the tabs, even if I hover over it (I
can Cmd-W it, though). I've also seen, more than once, seemingly randomly, that Safari refuses to allow me to switch to a Chinese input script; I'm forced to type it out in TextEdit then copy it over.
The Chinese input thing happened on 10.5 and 10.6 with Safari 4 and 5, the quit/close tab thing only happened in 10.6.
And Safari still takes up 1.2GB of memory after an hour or two of browsing, which it refuses to release until I quit it, forcing other apps to eat into my virtual memory. *sigh*
EDIT: Just found something else.. the href of a link no longer shows up in the status bar at the bottom of the window..