I just read the N standard (802.11n which will be 10x faster than 802.11g) will not be final approved until July 2007 so anything you buy now is nonstandard and may not be able to be upgraded via firmware. Also you have to buy the corresponding receiver cards in order to have the super speed work and it may not work, either. But you get the use of faster speed until 802.11n equipment is official.
With N standard at 540MB (theoretical) and the standard Ethernet at 100MB the deciding speed factor may be your Ethernet network. GigE, which will ship with some 802.11n wireless routers, is rated at 1000MB so be sure to get GigE capability when buying an 802.11n wireless router.
If you decide get a new router/WAP (wireless access point) make sure you check for firmware upgrades right away. I bought a Linksys router/WAP and it was behind several firmware upgrades right out of the box.
Doug