As I am going to work on a (possibly) commercial application which is supposed to work on various platforms (alright just Linux and OSX, Windows would be nice), I am looking for advise for some of the choices.

All of the questions are "religious" topics, but please forget that

First of all a description of what I want to do... I want to make a powerpoint-like application with the twist that one should be able of changing the presentation while it is running. That is, the editor should be shown on one screen while the presentation may run on an other. I am aware that I may have to go platform-specific for some parts of the program.

Since I am fairly proficient with C++ that is the language I am going to use.

The choices come in two parts, IDE and graphical toolkit. For IDE I have read here on the forum, and has come to the conclusion that Code::Blocks is good since, it gets good reviews and runs on both Windows and Linux. Are there any other good crossplatform options, they don't have to be free, though there is a limit to how much money I can spent on a commercial IDE.

As for toolkit, I have found WX Windows and GTK+, are there other options (apart from QT which costs lots of $$$ when you want to use it commercially). Which of the options would be the best choice? It should be mentioned that I have used GTK+ (briefly) before while I am completely new to WX.

Okay, so I won't answer you'd rather use Java for cross platform development

Well, actually you answered everything yourself: CB is a fantastic (crossplatform) IDE, although you don't want use their latest official release (1.0r2), but one of their latest builds, because the official release is really outdated and has very little to do with the current version. Another great IDE is eclipse, that is also able to handle c++ with the CDT-plugin.
About wxWindows: Well after our all favorite company "M$" talked to Julian Smart (the founder of the project) and pointed out that the trademark "Windows" is owned by them, Mr Smart decided (along with some compensation money) to change the name into wxWidgets But this is a great library, especially if you want free crossplatform C++. Although I love GTK, I even do prefer wxWidgets over it, because unlike GTK it is a very "clean" C++-API. My advice is: Give it a try!

eclipse would be my choice of ide. support for c++ and support for cvs, subversion, etc all with plugins.. works on both windows and linux, and is free. my favorite ide.

as far as windowing toolkit. my vote goes with QT, but i dont have the problem of paying for a license like you will. wxWidgets is spoken well of (there is also a book from prentice hall that is available for free, ill post the link when i find it)..

(btw, its wxwidgets now because microsoft owns the word windows)

Edit> didnt see your post Flesym, i wasnt trying to be an echo i swear..

Ok found the book myself... Here is a link to it, and some of the other free books he has written:

http://files.opencursus.org/bruce_perens_series/

yeh sorry i forgot to dig out the link. looks like you found a good one there though..

thanks

You're going to get as many responses to this as there are cross-platform languages to choose from.

It would probably be best to thoroughly design the application, then explore implementation choices. Select your target platforms, including operating-system versions, and try to map out exactly what would be needed to port this application to each one ...

... before you write any code at all!

Yes, it takes a lot of discipline to do that, and you'll get "itchy fingers," but persist.

C++ with WxWidgets is the best choice.