But if you buy it now, you won't have to buy another one next year. You'll just have the last year's model.
As for options, I don't the iPhone or PSP really give "options" like the DS. With the PSP, more games are supposed to be for download, so you basically wouldn't need the UMD drive at all in theory. The iPhone does away with older models (for the most part). The DSi is at least giving you one that's regular sized, and one that well, "XL." That's more of a real option.