Allright people I think I have decided about a couple of things. Thanks everyone for the input, it gave me a lot of stuff to think about.
- together with my girlfriend we have decided not to place a computer table in the living room (as we did in our previous home), simply because of the fact that we each have a laptop on which we usually work while sitting in the couch. The PC is only used for the attached printer and to store and backup digital photographs etc. So I will probably put the PC in my painting room. There I can use it to play music, directly upload digital photos, surf the web and post on my blog.
- I think I will go for one or two tables instead of a desk (thanks Midnight Lurker

). I think it will give me more options and more space. I will only need to find some cheap drawers or cupboards to store my stuff in, as well as a book case.
- My Dremel will also get a dedicated spot, and maybe I should invest in a small and cheap hairdryer (those travel models will do I think) rather than stealing my girlfriend's stuff every time.
- One or two paintiers: I had an offer from an old friend on the CMON forums to buy a second hand one and @Dragyn: I've sent you a PM about yours...
- A new painting light.
- I have a small cupboard left from my old room: it's about 80cm high and has a 60x60cm surface: perfect for my dedicated photo setup. I might consider buying a second light for it, my old painting light will be the first one.
That's about it for now. My painting studio also has a window. It might be cool if I could fit the painting table right underneath however I don't think this is possible since it's quite low. And I also don't know if I will want it, since it's oriented towards the south, I will be painting in direct sunlight in the afternoon...