I prefer "ultra vnc" over "real vnc" (file transfer feature is a good reason fro me).
Both are good over a local network, but over the internet they are too slow, neither one can beat pcanywhere.
Also, while working with several pcs accesible through VNC in a LAn, identfying each unit's ip/name may become a cumbersome task, in that case, you may want to check "VNC Neighborhood".