8GB is only really supposed to be sold online I believe although I did see some reports that some stores had it.
I think it's worth springing the extra cash for the 16GB. After the OS and system apps you only get something like 5.5GB of space for your own apps, data, and music on the 8GB model.
Yeah, but 5,5GB will be enough for me. I don't use more than 2GB on my phone. Plus I won't store music or movies on a tablet since whenever I need them I have wifi in range and they're on my Dropbox so I can stream them. So I only need the storage space for books and apps and for that 5,5GB is more than enough - I think the 8GB version is perfect for me.
I wish I could just go to Walmart or Best Buy and just get one. If I'll have to pay for shipping of the 8GB version I suppose I'd go with the 16GB one after all. The difference would be like 25$ and it would save me extra hassle.
edit: Apparently the Office Depot sells them?
http://www.officedepot.com/a/products/120697/Nexus-7-From-Google-7-Tablet/
If true I'll be happy to grab one next week.