Talking Merriam-Webster English Dictionary
The Talking Merriam-Webster Dictionary includes 75,000 definitions in 45,000 entries. The program can pronounce ten thousand of these words for you. In Basic Mode, the dictionary uses a main window for scrolling and search and a tabbed second window for definitions. In Advanced Mode, the program presents itself as one window with a Notes field to let you annotate the entries yourself. In both modes, the dictionary is quick and easy to use. The definitions I sampled appeared sound. I'd like to see language of origin for every word, but that may be a geeky wish that others don't share.
The accent issues from earlier versions have been fixed. The speakers now sound like native speakers of American English. The choice of spoken words could be better, though; surely we'd get more benefit from hearing "trompe l'oeil" than "troop," and I'd rather hear "aegis" than "advocate."
Paragon Software offers a number of different Merriam-Webster dictionaries, from smaller (Pocket, $16) to much bigger (Unabridged, $62), foreign language (various prices) and specialized (Medical, $43). Any of the programs can search the other dictionaries from the same interface.
Note: This demo version works indefinitely, but nag screens begin popping up after 100 definitions. Buying the full version removes the nag screens.