With the announcement of the new Nexus 7, we knew that the old one was going to be left to the history books, I don't think anyone actually thought that Google would keep selling it for something like $100, it just didn't make sense. As of today, the original Nexus 7 tablet is no longer available for purchase from the Play Store, the only Nexus 7 you can buy now is the new one, not even the old ASUS dock is still up there. All the pages are still up and you can check them out, but all the "buy now" options don't exist any more.
The new Nexus 7 seems like it will be the perfect evolution for an already great tablet, it has a much better display at full HD resolution, a more powerful processor with more memory with the S4 Pro and 2GB of RAM, dual cameras and it will even be available with LTE soon. Really, for $229 for the 16GB version who could still want the old model? The 32GB model is $269, both prices are for WiFi only models. 3G and LTE models should be added soon. Google managed to make a single LTE model for all carriers, having 6 LTE antennas for AT&T, T-Mobile and Verizon, all in a single device.
If you already have the old Nexus 7, don't feel too bad, it's still a very decent tablet that's about to get upgraded to Android 4.3 which should allow you to enjoy some of the new features like OpenGL ES 3.0 and Bluetooth Smart and obviously, you'll still be able to Chromecast like everyone else. If you don't want to wait for the OTA, Google has already posted the images on their developer site, so you can update manually but if you're rooted beware, Google made some security changes and root is not functional yet. Since the Galaxy Nexus is about to get Android 4.3 as well, you can be sure that you'll get a few more updates until the device falls into legacy territory, at the very least, the next major version of Android will be headed your way.
For those without the old Nexus 7, what are you waiting for? The new Nexus 7 will be available from next Tuesday, I'll even help you with the links: