I will say wired one is definetely more reliable than wireless,
sometimes wireless just get cut off for no reason.
Read about types of lan cables here:
http://www.donutey.com/ethernet.php
I am using a usb wireless adaptor on my comp, as my router is in
the living room and my comp is in my room. I will say that there is
not much difference in performance. My wireless adaptor can support
speed up to 54mbps, if you a 100mbps starhub cable plan, maybe the
wireless adaptor will bottleneck your speed(if u can really get
100mbps everytime u use)
I also use my wireless for torrent, im not a heavy torrenter,
but if there are seeds, there should be not a problem to get up to
speed