Most remote desktops apps on Android can get pretty pricey. So, when a $2 RDP/VNC-compatible solution comes along, we take notice. Jump Desktop, a comparatively small player in this app category, has knocked 80% off the normal price of $10. Not bad! The service is pretty fully featured, including multi-touch support, the ability to connect via WiFi or 3G, and even SSH tunnel support!
The app works for both Windows and Mac systems. Set up is relatively painless and uses your Gmail account to make the connection easy. If you'd prefer not to hand over your credentials to the most important sign in you have on Android, though, you can also set things up manually.