You didn't state if you are using XP pro or XP home.
wins support = Yes
netbios name = (my choice)
ldap suffix =
Since you have "wins support = Yes", then enter your samba server's IP address as the WINS address in the windows TCP/IP configuration. If you use a NAT router, then you may be able to enter it there instead and DHCP will supply this info if the XP computer uses DHCP.
Enter in the name of your Workgroup. That is probably the reason that your Samba server doesn't show up.
With your configuration, there are 3 services which should be running: smbd, nmbd and winbind.
You can check if they are with:
sudo /usr/sbin/rcsmb status
sudo /usr/sbin/rcnmb status
sudo /usr/sbin/winbind status
Also, when posting a config file, please put it inside [ code ] ... [ /code ] blocks (without the spaces I added to print it literally).