Buying a new router and adapter TODAY

Hi guys, I am making my home completely wireless this week (this Wed. so I would have to buy TODAY) and am buying either

LINKSYS WRT120N IEEE 802.3/3u, IEEE 802.11b/g, IEEE802.11n Draft 2 Wireless Home Router
http://www.newegg.com/Product/Product.aspx?Item=N82E16833124344

or

LINKSYS WRT54GL IEEE 802.3/3u, IEEE 802.11b/g Wireless-G Broadband Router
[url=http://www.newegg.com/Product/Product.aspx?Item=N82E16833124190]
http://www.newegg.com/Product/Prod [...] 6833124190[/url]

I will be using the router exclusively wirelessly but I do want ethernet ports incase I want to LAN. I will be connecting it with 2 laptops and one desktop wirelessly. The desktop is a gaming machine so it'll be a bandwidth hog. I am currently using a Model 2100 La Fonera with IEEE 802.11b / 802.11g (up to 54 Mbps.) ... and it unfortunately has no ethernet ports.

The desktop is in the same room as the router, but it is on the other side of the room and do not want any wires crossing my room or along any walls.

So, here are my issues.

1. My Desktop has no built in wifi and I'm not sure whether I should get a USB or PCI adapter.
2. Is it possible to go wireless and still game?
3. And ultimately, which router should I go with?

If you have any recommendations, suggestions or questions please do tell. If it matters my total price range after shipping is $80.

Thank you very much.

Thanks, I ordered the PCI with n combo.