[Arinoth]

Actually depends on the routers these day sswilson. I have a gigabit one that'll broadcast in N/G/B (individually or all three). Also, what you want to take into consideration is the maximum or ideal transfer speed that each protocol uses (N or G) will be approximately equally divided between the number of machines you have. This means
Regular G = 54 Mbps / 4 = 13.4 Mbps (ideal with full bars for your 3 pcs + 360)
G + = 108 Mbps / 4 = 27 Mbps (ideal with full bars for your 3 pcs + 360)
Wireless N = 300 / 4 = 75 Mbps (ideal with full bars).

So as you add more devices onto the wireless network your overall split wireless speed goes down.