This is a little old now, but I've been digging around looking for some info on 802.11n.
IEEE has informally assigned a group to investigate what needs and markets the next standard, 802.11n, should address, according to Brian Matthews, IEEE's publicity chair for 802.11. Throughput of the next standard hasn't been determined but is expected to be at least 100Mbps and could reach 320Mbps.
"What exists today meets the needs of 90 percent of the market," said Nogee. "The more standards that are set, the more complex the market will become...It's debatable if people will even notice going from 54Mbps to 100Mbps in most applications."
He brings up a good point about the market being OK with 802.11g, but for those of us that sling video around networks, faster wireless (and cheaper, hopefully) would be nice.