The best plugins I have ever seen come from Universal Audio and their UAD-1 card. These plugins are amazing but the hardware and plugins cost $ (from about 350 for the project pack and more for their other packages). However, these vintage compressors and modern reverbs are amazing. check out UniversalAudio.com and read about their digital products.

I have two of their DSP cards installed and sware bye their 1176, LA2A, Pultec, and reverbs.