Thank you, vga=... worked also on my XPS1710.
The only thing which yet bothers me is a very loud sound (sadly not caused by the loudspeakers!

), which for instance appears, when typing backspace in the terminal, or restarting ubuntu-live booted from DVD. The terminal offers an option to turn this sound off, but other programms like openoffice don't. So I would like do disable this sound globally. Is that possible (without recompiling the kernel)?