Draft 11n ≠ 100 Mbps Ethernet
Despite a certain networking publication's enthusiasm for the still not-fully-baked draft 802.11n wireless LAN technology, you can safely continue to install CAT 5e cabling without fear of wasting your hard-earned money. Wired Ethernet is not going to be replaced by 802.11n or any other wireless technology on the horizon anytime soon, if ever.
How do I make such a bold statement? Well, the facts really speak for themselves.