JoyDownload - Collection of free software and shareware programs to download
Meazure - What are the dimensions of that image? How big is this window?
Downzen - Downzen.com provides comprehensive reviews and downloads for software in an easy and reliable way.
ScreenRuler - ScreenRuler lets you measure objects on your Ubuntu desktop using six different metrics.
osalt - Find open source software alternatives to well-known commercial software.
Bluegrams Screen Ruler - A lightweight and configurable ruler tool for Windows Desktop.