How will Windows 10 affect my art software and games?

I've been looking through the internet for a while, but haven't found any straight forward answers.
As an artist I have tons of art software on my computer, such as SAI and Photoshop E8, Poser, Manga Studio… I also have a few games I'm very fond of. Minecraft (with tons of mods, mainly 1.7.10), GMod, Vindictus, WoW, Amnesia, Aeria Ignite, Maple Story… Soon to add Sims 3 and Sims 4 as well.

I just want to know if I install Windows 10, is it going to screw up any of my art programs? Is it going to mess up any of my games, and will Steam still be able to run W10? What about Technic Launcher?

All I've heard is that graphics will be better and there will be streaming from the XBox One…

It largely depends on the individual game, but Steam should run just fine on Windows 10. Photoshop will also either work or be patched to work. As for everything else, I'm not certain, though you could always run the game in compatibility mode if it doesn't.

Go on each website for the software and look for announcements or messages about windows 10. For example, the website for your anti-virus software might say, "we're ready for Windows 10." Then it should tell you about downloading patches, updates. If it doesn't say anything, then you can try e-mailing them.

It may or may not have any effect. Best thing to do is make a image backup of your computer using say something like Macrium Reflect or if your computer savy, Clonezilla. Upgrade and see what happens. At least you'll have a backup image of your system in case.