Guess I can help out with the crusading books, having read a few myself.

For a general overview focusing on politics and crusading ideology, check out the books of Jonathan Riley-Smith. He's one of the latest crusade historians, and has already published numerous books. I won't list all of them here, but I can mention the ones I've read; namely The First Crusaders 1095-1131 and The Crusades: A Short History (which isn't short at all). Riley-Smith's quite the scholar, which can be both good and bad depending on what you're looking for. There's an abundance of information in his books, but the writing can tend towards dryness at times, typically academic, the kind of book you'd read taking history classes at an university.

If you want the military aspects, try John France, especially his
Victory in the East: A Military History of the First Crusade. If you rather fancy a great and epic tale, the crusades trilogy of Steven Runciman is among the best ones out there.

I would also recommend The Crusades Through Arab Eyes by Amin Maalouf. As the title implies, it's quite biased, but the writing's great.