I just recently bought this Netgear router:
http://www.overclockers.co.uk/showproduct.php?prodid=NW-136-NG&groupid=46&catid=1596&subcat=It does a desktop PC (wired), a 360 (wifi N) a netbook (wifi G), our Wii and DSs, plus our mate's iPhones. Upgrading to a new router solved so many issues - also, it cleared up our problem with the Sky Player on the 360. That would seemingly overload our old router and so we'd have dismal performance when streaming stuff off Sky. Torrents would also overload the old one, but not an issue with this one.
As you can see, it's very reasonably-priced, so no need to go mental with your money.