Logos 4

I just got Logos Bible software a few months ago. It's great. I would recommend it to anyone. They just launched a version 4.0. You can check it out here.

Andy Naselli highlights what is great about it:

1. It syncs with iPhones. If you use a Logos 4 base package (Windows or Mac), you can access most of the your books on your iPhone at no additional charge.
2. It’s more efficient. It’s more intuitive, and it’s much faster.
3. It’s better looking. Here’s a sample screen shot (click to enlarge):

Here is some info for Mac users that you might want to read before you buy.