I enjoyed Rendezvous with Rama immensely, and also plowed through it in two days, despite reading two other books at the same time. Arther C. Clarke creates an engrossing world and populates with interesting mysteries - and to me, the most interesting was the utter lack of interest in humans, the complete irrelevancy of our actions to Rama itself. It struck me that alien contact might be like that. We always assume we'd be the centre of anyone's universe, but we may not be as interesting as we are to ourselves.
Another important aspect of the book to mention is the complete rationality with which all the characters act (with the possible exception of the Hermians.) Even the religious character acts swiftly, decisively, following the chain of command, and with a mind to issues larger than himself. The commander embodied this, making decisions that put peace and science above mere survival.
I might like to think First Contact would be handled like this, but somehow, I doubt it. But it is interesting to read a book premised on that idea.
This wasn't an action-based book, but I found it both fascinating and engrossing.