Well, look at it this way:
Wifi is generally slower than wired internet, but is often preferred simply because its so much more convenient - You can move around the house and whatnot, and use things like iPods, smartphones, etc. on your Wifi.
But if you're going to have a gaming PC, that means you'll have a monitor, mouse, keyboard, and computer, right?
You don't really move that around often, so if you can hook it up with a wire, then that's generally better. But for a laptop, Wifi is nicer because you can sit on your couch or whatever.
Also, maybe get your router/modem checked? Find out what speed your internet is supposed to be, then compare it to what it actually is? I had a friend in Canada who couldn't skype, due to their internet being extremely slow, but they got it checked, and found out their router had been broken for some time. They bought a new one, and their Wifi sped up a lot.
Ex: The Wifi that I'm supposed to be using right now is supposedly 50 mb/s (AT&T suuuucks down in the florida keys), but I downloaded Razer Game Booster earlier today at 1 kb/s (It later went up to 31 kb/s, which still sucked.) I checked what the speed was in my Network and Sharing center thingy on my computer, and it said it was 39 mb/s. "Liek what the fluffffff" (Any help there? xD)
At home I have xfinity, and it's pretty good. If you check my Youtube channel, MooclanTheCow, then you'll see what I mean. That's with the 50 mb/s plan, (Or is it the 100 mb/s?
) which is only a little bit more than the next one down. (I dunno if I'm writing this correctly.)