In Windows OS, please, use AppData\Local (%LocalAppData% in Win7) instead of AppData\Roaming (%AppData%)
The roaming folder is intended for synchronization with roaming profile storage, this is why all software should keep only small and absolutely necessary files here, which can make sense in other machine for the same user. Take look at browsers - they stores cache history in local folder and browser settings in roaming, this is correct. An average size of roaming profile for typical user is about 100..150MB (which can be easily transferred via LAN to any user's PC), but Bitcoin's folder have 16GB wich is inappropriate.
At the same time you can think about ability to manually specify storage location, because of such a huge size. Most modern PC have SSD with quite limited capacity (64, 80, 128) for system drive and separate HDD of several TB in size. Personally I have to create Symbolic Link to store Bitcoin's storage on alternative drive.