"I don't want to have a pc that is the best of the best, I don't want to have my pc always up to date. I just want to buy something that will last me the maximum time possible (from 7 to 10 years)"
You cannot expect someone else to pick up specific products for this criteria, since it is very subjective. Today's desktops, as someone suggested, can live up to 10 years. How healthy, or how up to date at that time is, yes very subjective. If it were me, I don't even plan to use my desktop 10 years later, although this desktop is mainly for game, light document work, and streaming movie only. 10 years later, I'm sure no matter how careful I manage this machine, it will be slower and need upgrade of storage, memory, and a few things, which may not be available in regular market because compatible components would be really outdated. For example, my previous computer needed a replacement GPU one time when it's about 5 years old, and it needed AGP card, which took me several days to secure, even for unreasonable price with poor performance, because no one was making AGP card any longer. Yes, even several years back already, 5 year old PC was badly outdated, and some key components were hard to find. After that, I kind of hoard left over component from old computers, although most likely I wouldn't use them ever, because of such case. For your information, I was involved in ThinkPad product development quite a long time , so I know how to find good components and still sometimes out of luck, even here in the US, where everything is abundant. When "future-proof" is considered, it should be understood as upgradability of some key modules to maximize potential of the existing platform, not as something to live up to 10 years as it is. That is misconcept.
If I would stretch, however, the best choice for you would be any I7 Haswell-K CPU + Z87 board with 10 year strength. For most "art-media program" I7's hyperthreading will be helpful, and later you can overclock it for more muscle power when it's needed. You want to have a Z board for OC, and for 10 year durability, you better find a reliable model. You can search your favorite online retailer for availability in your region, and narrow down to a few candidates based on user review. Then find expert review on those models to read about component quality and other features that you think would be useful. Then you can have better idea. Why Haswell/Z87, instead of IVB/Z77? Because if you see 10 years, you better start with the latest technology, in a hope that there will be still support for the platform at that time. The latest one will have more chance for that.