I use Remote Desktop and UltraVNC, both have there benifits. I usualy setup FreeSSH or copSSH (both are based on openSSH) on the machine to be controlled and do VNC or RDP over a SSH tunnel to secure it, this is only required over unsafe connections like wireless or via the internet.
Here is a good guide about how to do it
http://theillustratednetwork.mvps.or...esktopSSH.html
RDP has some quirks with regard to loging in and auto login out the current sessions. VNC on the other hand lets you to control the remote pc and allow local view/control at the remote pc. This feature is great for helping someone out or demonstrating a process to someone.
Regards