In what sense, exactly? A new local reference managing client?
JabRef is what I use currently, and it's pretty much complete as I see it, aside from perhaps having the ability to search within PDFs, and one or two other trivial features ...
For a short period I was thinking that a Android version of it would be great, but for me to use it it'd need to support more "weird" workflows like mine (where I keep all my bibtexs and pdfs and whatnot in source control).
On the other hand, if there was a "Sync to <foo>" style system, where I could somehow link up JabRef and Scirate (and perhaps other such websites, say if Journals started getting involved...), that'd be pretty cool. Which is basically what could be accomplished by a suitable Scirate API + local python tools...