10. Make Use Of Your Old Wireless B or G Gear
As mentioned, don't throw out your old networking gear after you upgrade to Wireless N! To get the best out of your new toys, you'll want the computers and devices equipped with the old clients to still use the old infrastructure.
Once you've upgraded everything, you might even find other purposes for it, such as to extend your network. If you want to tinker around with wireless stuff you could try out a replacement firmware, such as DD-WRT.
Eric Geier is an author of many computing and networking books, including Home Networking All-in-One Desk Reference For Dummies (Wiley 2008) and 100 Things You Need to Know about Microsoft Windows Vista (Que 2007).