This is a great thread idea. I used to teach a class on software that makes the seminary student/professor/pastor's life easier. Some day (in my non-existent spare time) I wanted to turn this into a blog.
When I evaluate all the software that I use for preparation and devotion two ones come up time and again for me - one free and one very expensive:
I
nstaverse - is perhaps the most useful thing for online Biblical research and for lovers of 2 Tim 3:14-17. It "instantly" pops up when you mouse over any biblical reference John 3:16, Jn. 3:16, etc. It is great. You get the KJV for free with the download but if you invest in any
Doxa (reformed software) package (like the Reformed Baptist Theological Collection, or the Kuyper or Berkhof collections) you get the ESV version free.
Logos - I have spent more time and more effort setting this up and as a former software applications instructor I have been both frustrated and awed at this product's overall capabilities. It does not compare in terms of speed to something like Bibleworks but its customization and extensibility far exceed any of its competitors. Half of my theological library is electronic and 80% of that is in Logos Libronix. These days if it is an ST or a commentary, I prefer to buy it digitally. It helps that I was given a free copy of the Scholars' Library edition at a Logos tech seminar I attended.