Categories: iPad, Phones and MobileWhich iPad should I buy?
Short Answer: 64GB either Wi-Fi or Wi-Fi + 4G
Longer Answer:
The new iPad retina display is, from all accounts, awesome. To take advantage of that beautiful display, app developers are going to include higher resolution images/graphics in their apps. These apps will get bigger in rapid fashion. 16GB, already paltry, is going to look laughable in a few weeks. This impacts you whether you purchase a new iPad or have a previous generation iPad. Why? The apps designed for the new iPad will include higher quality images than your older device will support. Further, in many cases they will include both the high resolution and low resolution versions of images. This is because downsampling the high-res images to work on the older displays would really slow down an app.
Bottom line:
If it is at all financially possible, get the 64GB version of the new iPad.
Additional reading: Macworld does an analysis of the file sizes of the iWork suite.