Nice network diagram editor?

Try these LibreOffice/OpenOffice galleries with Draw: http://www.vrt.com.au/downloads/vrt-network-equipment

CC licensed, also available in Fedora repos and the libreoffice extensions site.

UPDATE: v1.1 release added new darker variants (like VMware's shapes), and a set logical network symbols added - now near 200 symbols in 5 gallery themes.

I decided to move my diagrams to the cloud after I saw Cacoo. It's a very intuitive tool, having a lot of diagram and icons choices and mostly it has options for online collaboration. The only downside is that is a proprietary software :/

Here is my sample

Inkscape is all you need. For additional clip art graphics ('elements'), use openclipart.org. OpenClipart is actually built into Inkscape these days. There's really no need to resort to non-free apps.