Guild Wars: Jagged Bones
These guys had enough clue to have Hex Breaker on the JB necro and we didn't have a Wild Blow to get it off. He had Distortion as a panic button for warrior defense but wasn't dumb enough to cast one of his key spells (JB -> Death Nova -> Taste of Death) while he didn't have Hex Breaker up.
We did split against them but they could send back enough hex shutdown to slow down the split team while their massive pressure and energy engine overran the flag team. I spent quite a while thinking about the match and I'm not really sure what you can do about that build. If you can't shut down the Jagged Bones engine you're pretty much hosed because all those necros will be pumping out Infuse Health, Aegis and expensive hexes like no tomorrow due to the fact they effectively have 15 pips of energy regen.
There's a discussion thread on the best way to fix the problem over at GWGuru. I think that the real fix is to deal with Soul Reaping - I'm liking the energy regen options people are proposing. But that would be a major change requiring a lot of testing. A band aid solution like making Jagged Horrors give no Soul Reaping energy would be better than nothing right now.