I installed a Pioneer Avic F900 into my GTI. I also fitted a connects2 steering wheel adaptor which allows me to control the pioneer through the steering wheel. I've got fast forward/rewind, next/previous track, ATT, source select, volume etc.
The most up to date maps are awesome with lane guidance and Suna Traffic management. the Ipod interface is fantastic also. The unit can play dvds and divx and can take SD cards.
The only niggling issue I have is that because the unit has built in bluetooth, I can't use the bluetooth that was factory installed in the car as the unit has no external connectors for 3rd party phone systems. I also can't use the phone button on the steering wheel to answer calls.
There is a new series Pioneer deck out now which has a new 3D accelerated interface and all round better performance than my deck which is now a couple of years old, however it's RRP is $2999 I think which is a bit steep for me.
I picked my unit up for $1700 when new. I think the current model equal to mine is the F90BT.