Darned near all of them!
I am still searching the furniture to pay for Rock Rack - that may be the best amplifier emulation yet. I have BX_Control, and use it all the time. BX_Digital is equally brilliant. Shred Spread is a one-trick pony, but it does that one trick so well. Boom is also really cool, but I don't have much call for it. All of their equalizers sound great and are very useful - but be forewarned, their work flow takes some getting used to.