"professional plugins" is almost an oxymoron.
Many pros process out of the box with analog gear. For example, I see many studios that run Pro Tools systems through analog boards and then process everything in analog before going back to digital, essentially using PT for recording, playback, and possibly automation only.
It's a more difficult and expensive ramp-up, but in the longer term a better investment IMHO. A good outboard compressor will be with you for life, and not be made obsolete when version x of the operating system comes out or a newer version of the underlying software. It will also very likely sound better.
That said, Waves produces a good set of plugs, in particular the L2 and Restoration plugs if you are going to master your own material. Also check out Sony Oxford plugs, Algorithmix, Crane Song (for PT users), to name a few. It really depends on the type of processing that you want to perform.