What is the best software for remote PC/Desktop access?

I'm looking for an OS or software to run on one computer at home, and access and do stuff on the computer while at work and school. Something like TeamViewer, but with more features and less lag. I might not have the ability to install software on public school computer, but at work I can install anything.

edit: Just remembered that my work and school have pretty slow internet connections so that may be a big limiting factor.

I know you wanted an alternitive, but Teamviewer has a portable version that you can install on a usb stick.  http://portableapps.com/apps/utilities/teamviewer_portable

Teamviewer seems to work better then anything I've tried.