Same story. Internal storage fills up to about half way really quickly but then it just seems to stay around that level for me. No concerns about it for the moment.
I've started to get a notification that my internal storage is over 75% and would i like to transfer items over to my SD card. The only problem is that the stuff it would transfer wouldn't bring the storage back under 75%. I do have 1.5 GB in cache data from apps. Not sure if I should delete that though.