The only DRM'd books I've bought were .lit, and I promptly converted them to be able to read them on my reader. Which was the eBw 1150 at the time, I think, but now I have those books on my iLiad. So I just voted for #13.
I do have quite a few books in non-DRM mobipocket format, though, and I wasn't sure if you meant for us to vote for mobipocket in that case. I use converters to move unlocked files around between formats anyway, so I don't really care that much if a new reader supports the old formats, as long as I can convert to something the new device can read. I admit that I really like having FBReader on the iLiad, though, because it can read so many formats without conversion.
That being said, I bought the iLiad specifically to be able to read (and annotate) PDF journal articles, which I couldn't readily do on the eBookwise. (Many of them are "scanned" PDF, which I'd have to OCR and fiddle with to convert to text. The PDF->jpg converter for eBw hadn't come out yet when I made my decision.) Online journals seem to have pretty much standardized on PDF, so for us academic types, PDF support will probably continue to be important.