Are you talking internet or things like keyboards/mice, etc?
In the case of internet: Wireless internet sucks royal. Even with a "GREAT" wireless G access point, games get lag spikes and nothing downloads or runs nearly as fast. Wired is 10,000 times better than wireless 'net.
In the case of devices/controllers/etc: I use a wireless mouse, and I like my wireless controller for my 360, but otherwise I stick with wires. I also don't care for wireless headphones, I'm glad that my wireless headphones have a jack so I can still use a wire. I like my wireless mouse, it actually works perfect, doesn't need a stupid pad, and has lasted on the same battery for a year and a half now. I still have a wired keyboard and I intend to keep it that way, I just don't see the point in replacing something that ain't broken right now. I got a wireless mouse because they kept breaking or losing the ball whenever a cat would trip on the wire and knock it down (Read: Every day.) and I spent a fortune on mice, and every laser mouse with a wire I bought sucked. Especially if it was Logitech. Then I found a 29$ wireless laser mouse and its stuck with me through and through since, no cats ever knock it down since it has no wire and there's no ball to worry about, and I don't need to use those annoying floppy mouse pads that barely fit on my desk in the first place.