GPS is a hot ticket these days. One only has to look at the number of portable navigation systems on the market today to get an idea of just how popular these devices have become, and there seems to be no end in sight. The GPS gadget du jour? The new Pioneer AVIC-S2. The unit features a 3.5-inch touch screen and TeleAtlas maps of North America, and 1.7 million points of interest preloaded on a 1GB SD card. The AVIC-S2 also has integrated Bluetooth for hands-free cell phone use, and a built-in MP3 player. So, you know, it's pretty much like every other system out there. The Pioneer AVIC-S2 will be available later this month for $399.