So, after little thinking I have wrote the following:

# In repository we don't need to have:
# Compiled object files
*.o

# Generated MOC, resource and UI files
moc_*.cpp
qrc_*.cpp
ui_*.h

# Built windows .exe and linux binaries
# NOTE: PROJECT is a your project's name, analog of PROJECT.exe in Linux
*.exe
*.dll
PROJECT

# Windows-specific files
Thumbs.db
desktop.ini

# Editors temporary files 
*~

# Debug and Release directories (created under Windows, not Linux)
Debug/
Release/

Please ask, what needs to be added or fixed (especially for Windows - I haven't one under hand now. And Mac too [haven't work in it at all]).

I want to keep my repository clear :-)