Having an ereader has actually opened my scope when it comes to "size" of the content I read. Previously, I read novels of varying length, and I read short fiction either online or in collections or anthologies. I find I like breaking up my reading by reading a few short works in between the longer ones. With ebooks, this is breathtakingly simple to do because I can read all of those from one device, and the shorter works are more accessible.
As for any length limitations in either direction, I generally don't get much from flash fic (extremely short) pieces, but anything that is the equivalent of at least 7 or 8 pages works for me. On the other end of the spectrum, I'm a Stephen King fan and the unabridged ("author's cut") edition of The Stand didn't even phase me, and that hasn't changed since moving to ebooks.
Like others have mentioned, however long it takes to tell the story. As long as it doesn't stall out too horribly along the way, I'm good. I
am wary of books that can't live up to their promise. If something is billed as "epic fantasy" then it should be of epic length (or part of a series). If something claims to have a complicated, involved story with many amazing characters but clocks in at 45,000 words I'm not even going to bother. Beyond those types of considerations, size doesn't really matter.
(Off topic but sort of related - I get really ticked off when I find out I'm being set up for a cliffhanger with no hint of it beforehand. If it's going to be a series, TELL ME! especially if the author has no clue when (or even if) the next one will be available. And each part should have
some resolution, even if the primary storyline continues. Just chopping a long novel into three parts does not a series make. Serial, yes, but it should be billed as such. Okay, rant over.
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