It'll depend on basically 3 factors. What is your current PC hardware (if its older it could be a compelling upgrade, but if you have a GTX980, 290/RX 480 and higher it probably won't be quite as compelling but might not be horrible, but if you have a 1080 it won't really be an improvement). What games you play or want to play (latest games? exclusives? maybe older console games that haven't been re-released/ported/remastered to PC?). And then how you play (do you like modding games? Do you have friends that play console online?).
I'd probably recommend getting a Switch first, as its the most complimentary for PC (in that there's less overlap in game choices, and how you can play with it being portable). Then wait and see if you can get either a good holiday/Black Friday deal or maybe someone selling their One X/PS4 Pro with some games (which will be the most bang for buck). The less you spend on hardware the more money you have for games.
There's 3 main things that keep me sticking with PC. I have a Steam library already and it won't transfer over (I really hope we'll get there where we buy a license and then can play it on whatever platform). Which I don't own a lot of more recent games so not a huge deal for me (Steam sales are less amazing these days, and there's often pretty good sales on the consoles, plus getting used disc copies). The people I play games online with don't have any of the newer consoles (but have PCs so we can play on there). And then the last one is that sometimes there's an issue that makes a game near unplayable for me, and on PC I can usually find a mod that can salvage it some (an example, the first Dead Island game had a ridiculously low FOV, it felt like your character was drunk or something and it was giving me a headache; on PC I could mod it up which made the game much more tolerable/enjoyable; this type of thing tends to happen less with these more capable consoles and even some PC games are becoming basically unmoddable as they'll claim its a cheat/hack and then you can risk losing your account access - although I don't think that's common still a bit of a concern).
I'm personally going to hold off on Sony til the PS5 (not just because I think that'll happen sooner than later), as it'll be much more capable than the Pro even, it should have good backwards compatibility with PS4 games (so can get the exclusives later and likely with possibly improved graphics and/or performance; although personally I don't really care much about most of the PS4 exclusive), and I think there's a strong chance it'll have a much improved PSVR setup (which I personally will be interested in). The One X is compelling to me because it'd actually be an upgrade over my PC for 4K (which I just got a 4K TV finally), while being quieter, putting out less noise and heat, and it would be great for media (4K UHD player). But I'd only buy if I got a really good price. The Switch is compelling gamewise but still is kinda offputting (stuff like their ridiculous online setup, the controls I find cramped and hate the asymmetrical layout on such small controls, the Pro controller I don't love either and its price is straight up stupid I think), and I like the Gamecube controller/adapter thing for Smash Bros, but that's extra cost as well. And then my friends not having one kinda keeps me from buying as well (I'd be stuck playing with strangers...or worse, ATers ).