In a word, most of them (Score 1)

The one I use the most at the moment is something that comes with Xandros (http://xandros.com) called remote desktop viewer. Obviously a renamed but cool version of vnc. It hooks to all versions of vnc and scales my 1600 x 1200 desktop onto the 1024x768 laptop I use when not at the office. I have no trouble with it but it keeps people from reading over my shoulder cause no-one else I have shown it to can read anything that small. We also use tight vnc and original (realvnc) on different set ups. I think though Xandros did it best. You don't have to press to send special keys, in full view there is a small title bar that can be set to autohide and so you get the whole screen but can still get out without finger calistenix. I th9nk it originated with kde.