There's an interesting discussion at "Prosblogion" on the issue of whether there are degrees of being. Being myself a big fan of the degrees of being thesis, I'd say, yes, there are degrees of being. But my primary interest in this post is simply to clarify a few things that tend to obscure the discussion.
1. Yes, yes, things either are or are not. Despite the fact that this almost always arises whenever degrees of being are discussed, it is irrelevant. The question is not whether there is a middle state between being and not-being, but whether there is a gradation of being among the things that are. Just as being less good doesn't make it any less a fact that you are good, so having less being wouldn't make it any less a fact that you are.
2. While it might sound odd or irregular to talk about "degrees of existence," this seems to be a matter of linguistic accident; it sounds less odd or irregular to talk about "degrees of being" and even less odd or irregular to talk about "degrees of reality", despite the fact that these phrases appear to mean the same thing. In fact, it makes considerable sense even in ordinary discourse to say that 1) some things (e.g., rocks and dream-rocks) exist in different ways; and that 2) there is some sort of real gradation or hierarchy among these things according to these modalities of existence (e.g., rocks are more real than dream-rocks). So talk about the oddness of the language will not, I think, move the discussion anywhere; it's the sort of odd language we actually do occasionally use, although we're more comfortable using it when it's said one way than when it's said another (and naturally, it doesn't usually come up much). One can, of course, make all sorts of abstruse distinctions between "reality" and "existence"; and that's fine (and there are, in fact, reasons to do so as a matter of technical jargon) but if you are willing to do so, you have no business complaining about the oddness of the language. Despite this, it is a bit surprising how often the prejudice against degrees of being comes down simply to discomfort with the language. If there is a problem with the degrees of being thesis, language does not reflect it.
3. As far as I've ever been able to determine, and contrary to popular (i.e., popular philosophical) opinion, there has never been a non-question-begging argument against the thesis that there are degrees of being. (Gesturing vaguely at the existential quantifier, however heated the gesturing, is not an argument.)
(For a brief introduction of this general area of discussion, see this article in the SEP. It's a fairly good article, although the author, Barry Miller, engages in one of my pet peeves almost off the bat, by saying that the use of "is" for "exists" in English is archaic. It is not archaic (nor obsolete), but simply rare. It occasionally even comes up spontaneously in casual, informal discussion (particularly casual, informal discussion about certain philosophical issues). We may not often go around saying things like Alexander Pope's "Whatever Is, is Right," or Carlyle's "So much that was not is beginning to be," or the common tagline for Descartes, "I think therefore I am," but this is a far cry from saying it is an archaic usage. A usage that surfaces spontaneously in ordinary discussion can be considered neither archaic nor obsolete, however rare it may be.)