A recent article on Networkworld.com mentions how difficult it can be to recover information from smartphones and game consoles.

I can imagine smartphones are particularly difficult, given the constantly changing nature of the hardware in use and the proliferation of mobile operating systems such as Windows Mobile 7, Android, iphone OS, WebOS and BlackBerry OS. The modified or custom file systems can also be challenging as I've read that the xbox360 uses FATX and that the PS3 uses a proprietary version of ext2.

However a particular quote from the article that caught my eye was ""You can take a Wii onto the Internet and it doesn't save sites or browser history....If you type in a Web address and surf, 10 minutes later there's no record of it." Intrigued by this comment, a bit more digging came up with this paper [pdf] on Wii Forensics.

Dr Turnbull highlights the lack of internal storage (excluding the 256MB flash memory) and proprietary file system as being some of the difficulties in Wii Forensic analysis. The paper makes for interesting reading.