Recently, my internet service provider had upgraded my wireless router; now, instead of a Netgear router and a cable modem, it's this combination all-in-one router/modem made by Ubee. It claims that it supports a/b/g/n (which it does support N, because that's what all of my PCs use), but it can't hold a connection well with the older standards...
It doesn't end here; what's downright hilarious is that I can stream video from my computer to my PS3 without encountering problems (lag is very little, but you'll notice the occasional drop of a stream), but yet I can't play a single game in GT5 without getting disconnected after about five minutes of being connected in a room.
Since my ISP took back only the cable modem, I decided to attach my old Netgear wireless-G router to an Ethernet port in the back of the Ubee router/modem, configured connections with all game consoles in my home, and boom; profit. It's a little silly of a setup, but hey; it beats running Ethernet cable from many rooms across the house... 💡