At the risk of sounding like a logitech sales man, check out some of their stuff.
If you shop around you can normally get this stuff quite cheap, while its all good gaming gear.
G5 gaming mouse.
G11 or G15 keyboard (would suggest the older design, the new ones just crappy)
and their X line speakers are pretty good, as well as being dirt cheap.
Good quality 5.1 surround sound for £45, £30 used on ebay. 2.1 for around 15-20 (search Logitech X-210 for the 2.1, X-530 for the 5.1)
Wireless network adapters are dirt cheap. Wireless N adapter wont set you pack more than a tenner. and another 5 quid if you want a high db antenna to go with it. Just search around on some websites, all makes are pretty much the same. (dabs.com, aria.co.uk, scan, ebuyer, microdirect, overclockers, to name but a few)
At the end of the day, the parts are for you. you need to look around at whats out there and decide for yourself.