There are many wireless products available today, and more being released every day.  Wireless networks are probably the farthest along with respect to being able to replace their wired counterparts.  In most homes, it is possible to have a completely wireless network. 

Wireless network speeds now rival the speed of wired networks.  If all you do is access the Internet for web pages and email, use instant messaging, and print to a network printer, any of the WI-FI (802.11x) networks are more than fast enough.  Most people don't realize that the average high-speed Internet connection (cable modem or DSL) only gives you 500k download speeds.  The slowest WI-FI network is 11meg.  Event if you upgrade to a faster broadband connection, they max out at 3meg, still within the speed limits of WI-FI.

Where the maximum speed of a wired network can be useful is if you use your network for audio, video, or large file transfers. 

Cordless phones have been around for a long time.  In many instances you can even use a multi-handset capable system in order to place phones in all the key areas of the home.  But, also consider how you will connect a modem or fax machine if needed.  It is still wise to have wired telephone jacks in key locations.

Finally, the more wireless devices that are in your home, the greater the chance that they will interfere with one another. 

We recommend starting with a wired solution for everything.  Then, look at cost, your lifestyle, what you think you might do in the future, resale value, and budget and decide how much and what type of structured wiring you need.