I've used most of the products that have been listed in this thread (in addition to a few others) and I just wanted to say all of them have weaknesses. I realize everyone is under budget constraints particularly if you are delivery low cost or fee courses, but to try to find one product (or even two) to do everything in elearning (IMHO) is not going to happen and things will change anyway in two to three months when a new version of some program comes out that has new features. I think the saying goes "Jack of all trades, master of none" which I think certainly applies in terms of elearning software programs.
To me, it depends on what kind of training you are doing and how important screen capturing is to that process vs. whether you're mainly wanting to convert PowerPoint slides into flash files. I don't do a lot of screen capturing currently so I mainly use Articulate Presenter, Engage, and I do use SnagIt to do screen captures/recording, but I use lots of programs to create content. I use whatever tool allows me to do what I need to do in order to accomplish what I need.
Here's a brief rundown from my perspective. (These could have changed, because I don't have the latest versions of everything) I think I tried Captivate at one time, but don't remember enough about it to comment.
Camtasia- Using the built in recording, the audio quality was always sub-par compared to other tools and the player look options seemed very limiting.
SnagIt- It's only designed to do a few things, but it does them very well. At $49 bucks, it's the single best bargain in elearing. If you haven't upgraded to version 9, I highly recommend it.
Articulate Presenter- It's probably one of the easiest to use PowerPoint conversion tool on the market, but it's expensive. You really need to purchase the Engage program with it to create interactive exercises. As already mentioned, the built in quiz is very good.
Hot Potatoes- Easiest to use quiz creation program, but using Moodle you don't really need the quiz part of the program at all. Very good way to create flashcards, matching, and crossword puzzles and integrate them into Moodle. The Hot Potatoes module in Moodle does not render pages correctly if you are using 1.9 and a "custom corners" theme. Education license is free (If you make exercises available to the public) although the commercial license will run you around $135 I think. It's not a bad deal, but once again it only does a couple of things, but it does them well.
I guess I would use the analogy that a carpenter doesn't show up with just a hammer to do every job. There will be different needs at different times depending on what you are trying to accomplish. If there's an open source product, that's great. If there's not, then you have to decide how important it is to your classes to buy another program that can accomplish something else you want done or if it can do something quicker or better than your existing software.
As an example, I still have Pointecast Publisher which is somewhat equivalent to Articulate Presenter, but there were a couple of features that I developed a need for that it didn't have so I switched to Articulate. I don't like unnecessarily spending money, but I used Pointcast for two years. I don't look at it as wasting $400 on Pointcast. I look at it more as a lease in that I spent $200 per year to use software that allowed my online classes to prosper.