aha I see now. Big thanks mate. Didn't know that NetBios over TCP/IP is fall-back for newer direct TCP/IP.
I did as you suggested on the linux box and I got following:
tcp 0 0 0.0.0.0:445 0.0.0.0:* LISTEN
udp 0 0 0.0.0.0:137 0.0.0.0:*
udp 0 0 0.0.0.0:138 0.0.0.0:*
tcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN
Therefore I think it's safe now to disable NetBios on all my machines since i don't run any win2000 or win98

In addition to previous link that posted Ronny i will give another one here that i found and i think it can be of use to somebody else too. Here it is:
http://www.petri.co.il/whats_port_445_in_w2k_xp_2003.htmthanks again for all explanatory