Stereo16

This a easy and flexible sidechain plugin. Takes care of all my sidechaining needs, even if it's not your standard trance pumping. Essential.

This synth is THE FM synth. With it's intuitive matrix, six oscillators, 3 filters, decent FX, and a cool additive feature (way more to that than meets the eye), plus some interesting wave shaping capabilities, this is the synth you want (read need) for FM synthesis. You might want to check out some tutorials on it, since it can seem daunting at first and there's a lot you can do. Definitely happy it come's free with certain versions of FL Studio. (It's also available as a VST from Image Line)

This VST has a massive amount of sounds which are ready to use and just great. The FX sound incredible as well. However, it has very little ability to tweak sounds, which means it's harder to get something unique. The fact that it's sample based also means you're relying on presets completely although great sounding expansions keep on coming out. Basically I feel that it's great for getting into the feel for a track but then switching to something a little more versatile for some parts of a track.