The whole house is wired with two seperate networks each on Coax and Cat5e (2x Coax, 1xGigE, 1x4-line Phone). I currently have a 10/100 Router/Switch in the network panel that handles most of the rooms and supplies 802.11bg on 2.4GHz and 802.11n on 5.8GHz, each encrypted with a password (802.11n's password and encryption are up to Government specs and are for my personal use - guests can ask for the password to my 802.11g network for their devices). There's also an unmanaged TrendNet GigE switch in the Living Room allowing gigabit communication between devices there.
Eventually, the current Router/Switch will be moved solely into a Router/Wireless AP capacity, with another TrendNet unmanaged GigE switch being thrown in the closet for whole-house gigabit networking and gaming. The router runs DD-WRT firmware for more customization over settings, QoS, filtering, and firewall exceptions.
Devices in the Living Room are 100% wired:
Nintendo Wii (10/100 via USB)
Xbox 360 (10/100, gaming only)
Sony 60GB Playstation 3 (SACD/BD/CD/Audio Player, 10/100/1000)
Western Digital WDTV Live (10/100, used for HD DVD/DVD streaming, soon to be replaced by Netgear NTV550 for BD/ISO streaming)
Slingbox PRO (10/100)
There's also a Wired PC in the Office using a 10/100/1000 connection.
Wireless Devices primarily use 802.11g, due to a lack of full 802.11n support:
iPad (802.11n when available)
iPhone4 (802.11g, no support for 802.11a/n 5.8GHz)
HP Mini 311 Netbook (802.11g only)
Gigabit Ethernet, in my opinion, should be a basic feature of any new home, with fiber being the preferred "premium" backbone. As it stands, though, most builders still go "Cat-fif-wha?" when you mention Ethernet, so I doubt this will become the norm anytime soon. I quite like that the builder ran four seperate coms networks + security, but I'm disappointed that they ran Cat3 cable for the Security setup. I'm also disappointed that they didn't pull the spare inputs like they were asked, in case primary CATV/FTTH lines fail.
And for the numbers geeks out there, the incoming net connection is 30Mbps down and 1Mbps up, meaning everyone can stream Netflix or videos in 1080p without bogging down the gamers or network. It's a dream.