I wont pretend to be a expert on wireless connections, i just sign on and use it...for my PC build i will be where possible hardwired into the router but i am going to buy a wireless PCI card in case while moving soon i find myself in a situation i cannot hardwire connect. What i am after is something decent to be able to play games on or download without losing connection but also affordable, ideally something that will be universial and easy to connect to a wireless connection no matter who the provider is?
I would say try and stick with a wired connection if you can, but if you can't, these ones quite good in my experience. Not as good as wired but adequate. http://www.scan.co.uk/products/edimax-ew-7711in-150mbps-wireless-80211b-g-n-32-bit-pci-adapter http://www.scan.co.uk/products/edimax-ew-7612pin-300mbps-wireless-80211-b-g-n-pci-express-adapter Try this. i have an edimax card and its suitable for surfing and downloading as long as you've got a decent router. Its range is pretty good as well. One tip though. you'll still have to wire a connection if you want to play upto date games at the same pace as everyone else in the game really. The odd song or short movie or youtube are ok over wireless but for everything else you deffo want a wired connection. A lot of people will recommend cisco but as i am not familiar with them i wont give any bad advice on which cisco unit to choose.
The ones mentioned above should do the job easily unless your proximity to the router is not close enough, like mine. I personally use: http://www.scan.co.uk/products/netgear-wn311b-100pes-rangemax-wireless-n-pci-adapter It is very good and has a range of about 50 metres with 4-5 walls in between.