Good to read that someone likes the Mk3. I had a Mk3 Golf Driver as a teen - to those of my friends who didn't know about cars, they thought it was a GTI. It had the trim, etc but not the engine and brakes. Don't get me wrong - it was slow, drove like a hippo (which I called it), but I liked how it was.
Sorry to read about the mkiv - I know it was bland, but again - there was some excellent engineering in points (drain tap for coolant - MK5 doesn't have this), but the trim of the interior sold it to me. Recaro's were great, and the modding potential was huge. I just kept going with mine - wish I still had it.
MK5 - love it. I wish the trim was better than the scratchy grey plastic it has, but aside from that - it drives so well and looks good. No plans to change mine even though it will be 10 next March.
I have no experience of the mk6, or mk7, but I would love my next golf to be a Mk7 Clubsport - it has some decent extra bits like the Edition 30 & stands out even more to anyone who really knows their cars.