Um, sorry guys but I don't agree with going with just a b/g speed router/adapter. With the prices coming down so far on N speed equipment, you might as well make the jump to it now.
Here's my current router
(the price is usually around $50 as it's on sale often, though not right now).
Here's one I've used for many clients.
Not as many features, but still decent.
Here's one that's alright
, but only if you want to use DD-WRT. I've read good things about it from people who do use it that way, but the stock firmware is shotty from just a quick google search.
Here's an adapter.
FYI, almost ALWAYS, if you are going to be gaming, you should go wired. Just a little forewarning. Most hardcore gamers I know won't put up with wireless. It has it's limitations.