Laptops and tablets are all well and good but if you have the room and the money to make it good, you will get a much bigger bang for your buck with a standard PC.
If something breaks, you can usually replace it without scrapping the whole thing, which has been a big bonus to me once or twice, like when I blew it up by hoovering it.
Laptops are more versatile, but desktops are better value IMO.
I know everyone loves Apple for some reason but my Windows PC is fab. It's 8 years old but has had many affordable upgrades with no information lost and I can download stuff from wherever I like.
Also, although it isn't white, it didn't cost the earth.
Ask around. Most people have a computer guy they trust who knows a computer guy who can fix the things they can't. I'd ask them to build it, based on your needs.
Mine was mainly for graphics and streaming at the same time, which is hard on the system, but it was designed to cope because it was custom made.
It cost a lot less than buying something less suitable off the shelf at PC World.