An excellent point, JSWolf, and it would be really nice to have multiple format support, at least until a true 'standard' format emerges. Part of the reason they don't have more formats may be licensing. I expect that they could get the .LIT easily enough, assuming MacroHard's licensing fees were workable, but Mobipocket might be a problem since it's owned by Amazon, which we know is bringing out its own e-ink reading device (at some point), and I recall there were some hints of friction between them when the Reader first released (Amazon listed it for about 20 minutes and then it was gone -- still is, though they seem to have some accessories, which is interesting). Yes, they just worked a deal with iRex, but iRex didn't have a competing format like Sony does. Who knows what, if any, difference that might make?
There are other formats, of course, but there has to be some limit to how many they could cram support for into on-board memory, and how do they decide which to support and which not to? How many should they support? It's the same e-babel, on the micro-scale, and I think I'd rather see more of a push for a 'standard' format than that kind of perpetuation of the format tangle that we have now.
Of course all that's my own opinion, and I don't expect anyone else to share it, necessarily.
