Very basic 2D drafting?

I'm looking for  a Windows application that lets you draw simple objects with dimension lines.

Of course, what I want could be done manually with MS Word or any paint program, but I'd like something that allows you to edit the objects (does not convert them to bits) and automatically maintains dimension lines.

Basically I want the "Notepad" of 2D CAD programs.  :-)

In fact, I have found this site (http://www.freebyte.com/cad/cad.htm#2D3DCADSystems), but I've not tried any of them yet - just wondering if people have a recommendation before I start going through this list and trying them.

Thanks for any pointers and opinions!

  Mark