graphics - Visio alternatives

I need an alternative to Visio for making diagrams (particularly signal processing block diagrams) that includes some kind of custom stencils + connection points. I just spent 2 hours learning bits and pieces of Dia only to find that it has no rotational capabilities, not even 90 degree rotations. Otherwise it's great.

Any suggestions?

Answer

I just found out about yEd and am very happy with it.