Jump Desktop is the one I like. It supports both RDP and VNC so you can connect to a Mac or a PC from the same program. It supports left handed users and has a method that allows you to move the mouse pointer without hiding it under your finger.
And if you use XP, Vista or Windows 7 Pro editions you don't even have to load any special software on the PC.
I have windows xp and im kinda liki_ng this answer