Good plan to acquire just a few high-quality plugins and learn them well. If you have money to burn, the UAD line is hard to beat. For less money, the Native Instruments Vintage Compressors and Premium Tube series are excellent. They were developed by Softube, whose own Mix Bundle is worth a look.
My other current favorite EQ and compression plugins include:
Maag EQ4 - magical sounding character EQ
OverTone PTC-2A - great Pultec emulation for cheap
Klanghelm DC8C - very versatile and inexpensive compressor
Waves Renaissance Maxx bundle - classic workhorses, on sale right now
Always try a demo of a plugin before purchasing. Good luck!
Cheers,
Eddie