When I was young, church history was taboo to me. I grew up in a denomination that claimed (at least locally) exclusivity as the church; it claimed that it was an extension of the first-century church and all other manifestations (i.e., denominations) were false. (And yes, by extension, all those folks in them were bound for hell.)
So looking at church history was not a good thing to be doing...it raised too many questions.
As I've aged, I've of course looked into these things for myself, and found church history to be both fascinating and frightening at the same time. But mostly, I've found it to be enlightening. Hebrews 13:7-10 certainly teaches us that we should look at our past, and for good reasons.
I recently ran across an online article about why we should love studying church history. In it, the authors (Rick and Susanna, relatives of one of my favorite bloggers, Tim Challies) look at why church history is important.
There are a lot of church history books out there. Some are very specific to an individual or event, or a period of time. These are too numerous to mention. Others are more general, covering long periods of history in a more superficial way. These are a good place to start. Some are very academic in nature, and are about as much fun to read as the instructions that came with your most recent 'some assembly required' purchase from China (excuse me, Wal-mart). Others are written for the non-academic audience, and are much better. Of these, I recommend Justo Gonzalez's book for both readability and accuracy. It is two volumes, but CBD has a version with both in one hardcover volume, and the price is very reasonable.
Of the more specific books out there, one I recommend is a compilation of multiple specific events/people. It is called Turning Points by Mark Noll. Of course, one of the best places to start with a biography is the classic Here I Stand (Martin Luther) by Roland Bainton.
I should also mention, for those who like audio-format learning, that a semester church history course by a fantastic lecturer, Dr. David Calhoun of Covenant Theological Seminary, is available various places online. Here is a set of the first half (Ancient and Medieval church history), and here is a set of the second half (Reformation and Modern church history). You'll need to do a free registration to get them...really, it's free. These can be downloaded and burned to CD or MP3 player for easy listening. These lectures are engaging and enjoyable...not at all boring or overly academic, for having come from a seminary course.