Necro/?

New to the game here and I made a Necro. Any recommendations for the secondary class? What works well with a Necro? I was thinking a Monk but wasn't really sure seeing as I will most likely play a Monk at some point.

Totally up to you. Every class will have its advantages and disadvantages. There's no "good" or "bad" picks for your secondary.

I've had good results from a necro / mesmer combo - especially in group settings where you can drop a target's health like a rock.

It really depends on your play style. If you want to go a life stealing tank go warrior.
If you want to use DOT curses try mesmer. If you plan on minonating i recomend monk for heal area. Of course these are merely suggestions

Necros eventually get several spells that are simmilar to the mesmer "don't do that" spells. Combining these with the actual spells can be devastating for that build. I've also seen the elem as a second since armor doesn't affect much of the dmg necros do and ele dmg does (it has its benefits if their armor goes below about 60). Also seen the N/Mo to heal up after sacrificing health. Theres no real way to go wrong with a necro =).