Basically what my topic is. I just got to the 3rd disc and realize they are the best combo. Since the entire crystarium just opened up, I'm wondering if there are any new classes I should focus on for them. Hope you guys understand what I mean, thanks!

IMO you should always focus on the 3 main classes for each character.  Not only are they cheaper CP-wise than investing in the other "off-roles", but  the upgrades and spells you'll be getting will be much more powerful.  After you max out those 3 roles then you can worry about going back and adding other roles.
 
Also you're not done with the game yet, so expect more Crystarium levels  to come. =)

Alright cool, thanks a lot! I was getting that kind of panic you get when everything opens up in an RPG and you don't know what to do all of a sudden. But now I'll feel better knowing that I should just really stick with the main classes... Phew..

I put a lot of work into Saboteur for Fang and Vanille, proved to be incredibly useful.

Yeah I've found buffing and debuffing to be really easy and useful since you don't have to actually waste time doing it yourself.. It's the most useful and annoying thing in a game :)