Wired is always better than wireless, because theres no interference from the air or through a floor. But since it's not practical in your case, wireless would be the way to go.
...lol...I have a computer in the living room, and the router is in my bedroom, and I have a 25ft wire, running up the ceiling. I would of gone wireless, but I had this giant roll of ethernet cable.
I'm not sure what wireless card to go for, as networking is not really my thing.