I'm new to Linux but not to app development. I come from a RealBasic on a Mac background.
I've accepted that I need to learn a new language to develop for Linux (since RB won't run on 64 bit distros and is a cloed proprietary language) but I want to make sure I pick the right one.
I've been looking at Python and was all set to go until I read that PyGTK is becoming obsolete with the introduction of GTK 3. Is this true? The Ubuntu developer website stills seems to recommend it with Glade for the UI but I want to make sure that I don't learn something that's on the way out!
The short answer is no.
PyGTK is being phased out and replaced with PyGObject as the widget set upgrades from GTK+2 to GTK+3. As of Oneiric all 'native' ubuntu applications run using the GTK+3 set.
On a personal note, fairly recently I started developing an application in Python, and having looked into it I decided to use Python3 with PySide (which is Qt4 instead of GTK+3) because I found that Python 3 would be the standard in the year or so it took me to write the program, and because Qt4 has a some very good documentation, and some first class development software (just have a trail of Qt 4 Designer...)