Samba server not visible from Win network
You've covered my usual suspects, but there is one word I didn't see in there and that's iptables. Could it be as easy as not having opened the right holes in the on-by-default firewall? I have had that whack me a time or three.
I suggest you to use system-config-firewall, a simple gui that can make these choice for you, anyway these rules should work:
-A INPUT -p tcp -m tcp -m multiport --dports 445,139 -m state --state NEW -j ACCEPT
-A INPUT -p udp -m udp -m multiport --dports 138,137,139 -m state --state NEW -j ACCEPT