I tend to enjoy the longer novels, Clan of Cave Bear, Outlander, etc. I also LOVE series, I like to get to know the characters, see what they are doing next, watch them develope. I don't think it's a coincidence that the 2 books mentioned above are both part of long series' and long books. I have also re-read both series' several times and enjoyed them each time through. Now that I have an eBook reader I pay attention to the "Reading time" and KB of the books to get an idea of how 'big' it is.
On the other side of the coin, I love to read YA eBooks because they are fast and easy reads. It all depends on my mood I guess. Even with YA eBooks I still tend to gravitate towards series, fast read with more to come I guess.