I added a wireless (Wi-Fi enabled) printer to our home network over the holidays. With three of us needing to print from three different computers, one of which is a Mac, this seemed like a good way to go. The appeal of a Wi-Fi printer was not only the ability to use it from any machine, but also the freedom to put it anywhere in the house without having to tether it to a computer or the router. Think kitchen counter, bookshelf, etc.
We decided on the HP 6840 Color Inkjet printer, which has 802.11g capability built-in. It also has an Ethernet port for a wired network connection, plus a USB connector for direct use from a single computer. When used in wireless mode a built-in signal strength indicator on the front panel lets you know you're still within range of your router, and the only thing coming out the back of the printer is the AC power cord. Sweet.
Setup was fairly painless: install the software from the CD-ROM, configure the printer, and go. We chose to give our printer a fixed IP address, and on our Windows® machines it was then necessary to go to the Ports page of the Printer Properties dialog and add a port for that address. If that step was in the instructions from HP I didn't see it, but other than that the instructions were simple and complete.
So far, our experience with this printer has been very positive. My only disappointment is that it has only two ink cartridges - black and color - which of course means you have to replace all the colors when one runs out, but I knew this going in. Our intended use is mainly for everyday printing, but the HP 6840 is also a photo printer with a front slot for feeding photo-quality paper and a PictBridge connector for digital cameras. PC Magazine has a review of this printer here.