Action RPG Maker - Engine 001
A very promising rpg maker game creation engine that's being developed by two guys from Canada that are constantly coming out with new versions. 001 has been around for a while now, and is starting to get a very good community. It has a pretty interesting approach to scripting that requires no programming knowledge. Sometimes it goes overboard with the built-in features, like its weather effects, treasure chests, doors and even to go as far as having turrets. However, it does a pretty good job for making interesting items and tile-sets with very little work at all. 001 has a built-in feature to create, literally, unlimited different rpg or action characters with a few clicks of a button. The site contains a pretty useful wiki and has a section to share created resources amongst users.
Click here to download the Action RPG Maker
A maker that has been around for quite some time written by professor from the Netherlands. It has a nice library of games made by the community. It's fairly open-ended. The 3D features are not very remarkable. However, it does a pretty good job at tying events together making it fairly user-friendly. Game Maker does expect a lot from the user in terms of resources. Similarly to other makers, it is quite visual oriented and lends itself to being a useful tool for educational purposes. Since it has been around for quite a while, there is a nice help section to the site that should definitely be consulted.
RPG Maker XP
The current leading rpg maker. Probably more due to its roots in console games, its marketing or its immense inclusion of good art; definitely not for the quality of the software. It still, even after being the sixth maker in the series, it shows very little improvement. In fact, with the release of the XP version, it is as if they took out some features to include some newer ones. To give this version some credit, it does include Ruby, an open-source programming language that can be used to give some power to this maker. As with the other versions, it has quite a lot of power in terms of stats and elements, used thoroughly by items and magic.
RPG Maker VX
The new version from the RPG Maker series. It is currently still under development, but promises very little new from RPG Maker XP, aside from better support for treasure chests and doors - which could be done fine before.