I currently pay Google $5/year for 20GB. I use half of this. I'm supposed to be really excited about what a good deal it is that I can pay five times as much for five times as much storage that I'm not using...?
I have a similar plan. I've filled up my gmail and picasa/G+ free storage, and am using ~6gb out of the 20 that I'm buying.
Current plan: 20GB for $5/year ($0.41/mo) => $0.25/GB/year New Plan 1: 100GB for $23.88/year => $0.24/GB/year New Plan 2: 1TB for $119.88/year => $0.12/GB/year
The 100GB plan is not a better deal for me, especially if I'm unlikely to fill the 100GB. The 1TB plan could be a better deal but only for someone using more than 500GB.