Davar - This piece of software is great for reading and doing comparisons of texts in the original languages. It is also very helpful because of its dictionaries. Both Davar 2.4 and 3.0 can be useful. Synchronous scrolling is one of the highlights for both. This is the best free application for study in the original languages.

Sword - This is an opensource project for Bible software. It has many modules to choose from. There are also many derivative projects. The GUI is fairly unattractive, and hasn't had any recent major overhauls.

The Word - This is another good piece of software that looks a little more attractive than Sword. Sword modules can also be converted for use.