I don't need to say much about Red Giant (check them out now!). They kind of speak for themselves.
I love their suite of products, and if I could afford it I would buy all of it.
Of my favorites: - Particular - Shine - 3D Glow
I also love the Magic Bullet products. I'm not talking about that amazing machine that makes your food for you. It's the awesome color correction products that make your digital footage look pretty much any way you want to make it look.
Check them out today - HERE (Quick Looks is a great intro and cheap too) All plug-ins work best with After Effects too.
And just check out what you can do with Particular 2.