Any brand will do, although some manufacturers will want you to buy their kit exclusively, there's nothing stopping you from a bit of mix n match, Belkin adapters will work with Netgear routers for example.
The main differences is in speed (of connection) older types are rated at about 54mbps more recent ones are 128 mbps or more. These figures are best possible connection speed and in practice are not really achievable in the home or office environment.
Argos do a good selection as do PC World, Maplins, Dabs, ebuyer etc the choice is yours really.