As far as farming your own books goes: So long as you start hunting for them when you're able to get the skill, you won't be too high to get the drop. Wait too long and the mobs will be darkblue.
Someone made a big list of where every spellbook dropped from what mob (or you can always use l2 wh).
I liked in OB, being blind to what skills i get in the next set so I would look forward to seeing what I would get, now I know what I get at level 80 and being years from it :P