Mesmer question

I'm making a mesmer and I can't really decide on a secondary for him. It's an RPG char and I want to try and make him a "disrupt every spell that foe casts" build. Also, I pretty much want to make him a nightmare for monks.

I'd recommend mesmer/necro. The Curses line can supplement your mesmering, plus it gives you the best enchantment removal around, and hexes to increase damage or decrease healing received by the target. It also has a lot of skills that work well with only a moderate investment in the attribute, and attribute points are frequently tight for mesmers.