Olive Tree Software - very comprehensive range of free and paid modules; in my opinion this is the very best for mobile devices.
Accordance - an excellent programme for the iPad, iPhone etc.
You Version - a very compact and convenient app - a very interesting app, with the bible in very many languages. Some of the versions are audio, which is very practical.

Accordance - the programme for MACs; a full adaptation for PC is now available. It is the cadillac of bible programmes.
Bible Works - the standard programme for PCs
Logos Bible Software - for MACs and PCs
Laridian - powerful suite of software for PCs and mobile devices
Olive Tree Software - a desktop version for MACs which should prove very handy and not so expensive has just become available. Olive Tree have just produced a version for Windows 7.

E-Sword - a completely free programme for PCs
Bible Explorer - a completely free programme for MACs and PCs
Bible Database - free programme with 200 translations
Theophilus - free multilingual bible programme for PCs
The Word - free programme for PCs (only, I think)
Davar3 - free programme for PCs