My signature says it all.
I love the SatNav and with the Traffic Management function ON have never come to a halt on any major route, but have always kept moving, as it navigates you around any traffic jam, even on the Continent. I personally find the sound system more than adequate when travelling. It isn't a concert hall after all.
Air Con, not just useful in Summer but even more so in Winter.
Media In. I have 500hrs of MP3's on my USB stick so haven't repeated it yet when using that rather than the radio.
Don't have Bluetooth as I don't answer the phone when driving.
VW WiFi - expensive and better systems available.
Zenon Lights - if it floats your boat, but I find the normal lights more than adequate.
Auto lights/wipers, fine if you can't be bothered to find the switch and have money to spend, also more expensive windscreen replacement.
Side bars and wheels are really personal choices and certainly something that can be added later.
Leather seats, OK if you like them. Having had them on many previous vehicles I find them too hot in summer with shorts on and dislike sliding around on the seats. If the seats are proper bucket seats then that's better.
Full floor carpets from QTM, and I have the Autoglym Lifeshine system with 3 yr Guarantee. Some say it is expensive etc: but you get £80 + worth of products in a top up kit to keep the van sparkling and a 3 yr guarantee which works. Eventually when the seats look a little tired then I'll get the Brandrup 2nd skin covers or get them professionally recovered. Can't see the point of covering the seats with seat covers if you intend to keep the vehicle.
My California is used every day.