The Count of Monti Cristo is a really fun book. It was published as a serial and was kind of like the Breaking Bad or Game of Thrones of 1850s Paris that everyone was talking about at the time. It's fun to read for both the revenge story itself and for the implicit look into the history of the French Revolution and what the life of a (dramatized) high roller was like back then.
Oh yes, the unabridged version is huge - and quite daunting at first - but once you let the thing just flow over you, it's a real great slow burner of a revenge story. Very highly recommended if you like a long read.
Read it as a serial. The last time I read it, a couple of years ago, I read a chapter each night. The hardest part was not reading a second or third chapter each night.
Another approach would be to read it as published. That's something like 18 parts in as many months.