Well... where do I begin?? LOL
I'm a gadget oriented type of guy and I've done a lot of outdorsy stuff over the years, so I know how much easier your life could be if you only had "that thing".
So, since this is my very first campervan and after loosing a lot of stuff in my travels in the recent years I bought quite a few things to get ourselves going... gadget-wise:
Power inverter with 4 USB ports
Camping Waterproof LED light with a huge battery that can also charge phone/tablet
Digital Tyre inflator (a small little thing but mighty)
New Bluetooth Stereo and some decent speakers
A toolkit to have on board at all times (ultra handy)
A battery powered electric shower for outdoor use. We spend a lot of time at the beach and it's the best invention ever!! Drop it in a bucket of water and presto!
I think that's pretty much it for now, of course, add all the cutlery, first aid kit, tyre repair kit, etc, etc... even some new curtins
Cheers,
Rami