I don't know what you use that space for, but you could store things in the cloud. Google Music is great for this. You could delete things once you are done with them.
If "expansion" is your most important feature, then this isn't the phone for you.
I wish Google would let me buy more than 20,000 songs. I haven't looked at my total count, but it's way over that, and there's no way I can see to buy more, even if I wanted to.
I have easily 10gb of pictures that I can show anyone as long as I have my phone. Also, at least 15gb of music and I'm about to install Debian just because I can.
