AntConc (Windows, Mac og Linux, free) http://www.laurenceanthony.net
The IMS Open Corpus Workbench (CWB), Linux, Windows, free http://cwb.sourceforge.net/
WordSmith (Windows, 50 pounds): http://www.lexically.net/wordsmith/
Concordance (Windows, 55 pounds) http://www.concordancesoftware.co.uk
MonoConc (Windows, $85) http://www.athel.com/mono.html
PhraseContext (Windows, 35 Euro) http://www.hjkm.dk/
R (with some programming) Quantitative Corpus Linguistics with R: A Practical Introduction by Stefan Th. Gries
For social sciences
Atlas.Ti http://www.atlasti.com/de/
Nudist
http://www.springerlink.com/content/uxj45917q3207417/
http://caabi.ba.ttu.edu/Paper/Vasuki/Vasuki%20-%20NUDIST%20notes%28HTML%29.htm