I use normally a combination of different plugins to get the best result. My vocal strip starts with a Waves de-esser - then UAD 1176 to cut the peaks - then UAD LA-2A to make the vocals sounding smoother - then a Sonnox EQ or SSL Duende X-EQ. Sometimes the EQ is pre compressor sometimes post. I love the sound of the Sonnox EQ on vocals very much. It sounds very smooth for a digital EQ.
After that I add some hardware effects on them like a ducking delay from my t.c. electronic D-two and a hall or plate programm from Lexicon 300 or Eventide DSP4000 depending from style and source signal.
A very simple and sometimes unbelievable good sounding all-in-one plugin is the Waves Rennaisance Vox. It has only a gate and a compressor, but sounds even today awsome.
It's easy to use for beginners and semi-profs, but can also does a good job for professionals.
Before I had that UAD, Sonnox and Duende stuff I used the Rvox very often with good results.
Another all-in-one plugin for vocals could be the ssl duende vocalstrip. I will try it in the future after my current production.
Instruments: AKAI S1100,EMU Ultra E6400,Kurzweil K2000,Korg WS EX,Roland S750,D550,JD990,MKS70,SH101,Waldorf Blofeld,Ensoniq SQ80.
Studio gear Lexicon 300,Eventide DSP4000,Lexicon MPX1,Roland SRV2000/330,RSP Intelliverb,T.C. D-two,Korg SDD2000,Electrix Warp Factory,MXR Phase 90,Edison EX1,T.C. Finalizer+, DBX166A,166XL,160,286A,Dualfex II,Mackie 1604VLZ pro,Mackie Control,RME AIO PCIe,UAD2 Solo,PC Intel Core i7 2600 4x3.40GHz,Steinberg Cubase 6.5,MOTU Midiexpress 128,Ultrasone Signature PRO