Well, as far as pluggins go Waves, sonnox, and UAD offerings are pretty common in professional studios. Outboard stuff your looking at eventide, lexicon, t.c electronic, Neve, dbx, Focusrite, Universal Audio, Manley, and API. These as well as other offerings are some common, high-end brands. What is good for you will be determined by what sound characteristics you want/expect from a piece of equipment. Most expensive doesn't always mean it's the best for your needs.
If you like the sound of a line 6 spider, check out their POD, Toneport, and amp simulator software. "amplitube" by IK Multimedia offers a free version of their amp sim software i think.
If you describe in more detail what you have, and what you want from it, you'll get more specific recommendations.