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Do anyone use wxWidows ?

Many people use wxWindows. I think the site http://www.wxwindows.org/ keeps lists of examples.

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I juts thinking to base my staff on it or to use the standard way - GTKor KDE ? Some suggestion ?

It depends how portable you wish your program to be. wxWindows can run in lots of places and make a reasonable attempt at *looking* correct, although it can't integrate as well with GNOME or KDE.

I like to see people develop GNUstep, but that's another story.

I would choose wxWindows over GNUstep; wxWindows runs on Unix variants, MacOS (inc. < 10) and Windows; whereas GNUstep only really runs on Unix variants.

wxWindows is written in C++ against GNUstep in Objective C. (Though I suppose whether this is an advantage or disadvantage is enturely a matter of opinion ;) )

wxWindows is at a further stage of development. (2.4.2 against 1.9 & 0.9.1)

Cheers, Richard