Kst

Kst is a viewing and plotting tool available (you may be interested in some benchmarks) and has built-in data analysis functionality. Kst is very user-friendly and contains many powerful built-in features and is expandable with plugins and extensions. It features robust plotting of live "streaming" data, keyboard and mouse plot manipulation, plugins and extensions support, and large selection of built-in plotting and data manipulation functions, such as histograms, equations, and power spectra.