Hi Peter, I think the disnction you have made between mind maps and concept maps is an important one and I agree the discipline of describing the relationship between entities is important, but I dont think its always necessary so I like the idea of learning just one tool that can be used for both kinds of diagrams.Ive used Xmind http://www.xmind.net/ a bit and it seems quite easy to use. Its similar to Cmap but seems to offer a greater variety of diagramming styles and more richly annotated diagrams if you need them, but it can also be used to produce simple mind maps.
Stephen