A Year? Or Less?

I read this interesting article last week. To summarize, it highlights YA series that are being published quicker than conventional wisdom. Some publishing houses are producing each book less than a year apart, which is what traditionally has been the spacing for books in teen series. Aside from the logistical concerns (these books have to be written and revised and edited and designed and printed and so on and so on), I think it’s a great idea to publish books closer together. There are some series that although I liked the first book my enthusiasm for it isn’t going to keep me going for a whole year (sorry Nightshade series and Chemical Garden Trilogy). I have only so much time to read the books I want to read—so if I can read each book in a series one, two, three the momentum is there and I get the gratification of finishing a series, even if it’s only an okay one. But if I have to wait a whole year…I might just never pick up book two. Thoughts? Are there any series (besides Harry Potter, of course!) that you found worth the wait even if it was longer than a year between two books?