I have a number of Samba-based devices in my home (a NAS, a DVB-T decoder, a media center, an Ubuntu PC) and they all have some troubles with my Windows 7 based systems (desktop + 2 notebooks). They often don't even see the computer on the network. I tried enabling and disabling almost every setting (firewall, encryption key size, password based sharing, some registry keys to enable anonymous as everyone) but without real effects.
Is this a known issue? How can I solve or workaround it?