vb is the most popular. I think it's probably the easiest as well, but I don't know it so I can't really say. C++ is probably next on the list and I saw one guy who used delphi at camsys.
indeed some tools look like they have a "vb-style". i also think that the 3ds max script editor is much used for the exporters etc.
im learning vb now on school, making a calculator :D
but i doubt that i will ever make a tool for wc3 with it. (dont intent do eather, wouldnt have the slightest idea how/what)
Delphi all the way, iv been using it since 1.0 its at 7.0 now and all i have to say it kicks some major ***, especialy when comparing it with VB. I do use vs .net c++ sometimes (directx) but when it comes to devoplment time and ease delphi takes the cake... AND now you can download it for free, well atleast the stripped down personal edition.