Dragon Naturally Speaking is perhaps the most well known voice recognition software in use by the ordinary person. I've found it very helpful at times when my hands are not all that functional! It can take dictation, control web browsing, or work with a spreadsheet. Version 12 has expanded useability that makes it even better for those with upper extremity limitation.
See the link below for a product review.
Dragon Naturally Speaking - Voice Recognition

Virginia Hixson
Ergonomics Editor