I find it strange that Gmail offers two times more free storage than Google's online storage service. While the files created using Google Docs apps don't count towards the free storage limit, there are many other files that can be uploaded. I also find it strange to see that Google Music can store up to 20,000 of music files for free and that's more than 80 GB of free storage.
Google Drive should be the place where you can find all your files. Right now, photos and videos are stored using Picasa Web Albums, music files are stored in Google Music, documents are stored in Google Docs/Drive and many files are stored in Gmail.