Pronouncing that a given device doesn't need any more storage is a near-foolproof recipe for looking stupid somewhere down the line. However, I'm sceptical that many people need a 16GB mini-SD card for their phone.
SanDisk next month will start offering a 16GB microSD card, which — unsurprisingly given the format — is aimed at the mobile phone market. The SD card will set you back $141, and will initially only be available in Crazy John's. (There's also an M2 model for Sony Ericsson models, but I'm not sure how many people will need to get that niche.)
That amount of capacity inevitably leads to the question: how are you supposed to fill up that space? Pictures might be one potential answer, but 16GB will give you a hell of a lot of semi-quality phone shots. Indeed, the whole Pictures folder on my PC doesn't take up that much space.
The other obvious candidate would be video, but again, it's debatable that you need that much space for video that's viewable on a phone screen. My 8GB iPod Touch can handle an entire US sitcom season and still have plenty of room to spare.
Not everyone will agree, of course. For its announcement, SanDisk even rolled out a tame analyst, Avi Greengart from Current Analysis, who made the following observation: "Flash memory cards have increased in storage capacity, but even an 8GB card may be too small for anyone with GPS map data, a few movies, a game or two, a presentation file and other applications."
But if this is you, then I suggest you re-compress your movies into a more screen-friendly alternative and stop overloading your PowerPoint presentations with meaningless graphics. Save the capacity for where you really can use it — on a desktop PC where the OS will reclaim it in the blink of an eye.