I find that being a member of more than one digital library helps with the 'hold' problem. I have access to 4 digital libraries (soon to be 5) and, among them, I've been able to either avoid the waits or, at the very least, not have to wait too long for the books I want to read, especially the popular ones.
I have access to a very small digital library with only audio books and was able to get the Stieg Larsson books with no wait. And between 2 other libraries, I got the Hunger Games trilogy with less than a week wait.
Something else I've noticed is that there is little to no wait list for mobipocket books and the audiobooks in WMA format.
I'm glad to not have to depend on library lending to get books, though; I notice some books have wait lists as long as 70 persons (
) - I'd never be able to wait so long!