Think at some point people will own or have had owned all consoles up to date(not me, I was specific with my choices) for the simple fact is that there will always be a game on each console you like/want to play, but isn't on the other console.
So for me I want:
PS3 again for GT5&6, Last of us(never played it) and maybe check out uncharted, think that's about it to warrant the purchase and free net.
360 again to own the Star Wars edition(only had the mw3 other than normals), play forza 2 & NFS:Shift I own still(not on the list for x1)
Wii U for mario maker, mario karts and fact I never owned one.
Ps4 for wipeout, horizon, no mans sky, farpoint, killzone, infamous, last of us, driveclub and never owned one and perhaps try out VR.
I've got lots of dos box games on pc hdd of old favourites which if I'm honest are not living up to their nostalgia, but I can't be bothered with my mega drive or game cube, and mario kart 64 gets boring on your own like all mario karts, for the ps2 I do have crazy taxi and simpsons hit & run amongst crash bandicoot, but other than Gran turismo there's nothing any more to keep the retro consoles that a PS3 fat 60gb couldn't do, Goldeneye on 64 is awful now, so think I'm going to have to sell it, all the fun of childhood gaming gone on those consoles pretty much I feel and got no space for collecting them all.
My laptop is only good for some old games, but star craft is playable so I'm happy with that, hopefully 2 will work well along with the older hitman games.