Start with what you know. If it's Organ, well you have the classics Hamond B3, Vox and Farfisa Compact Deluxe. If it's electric pianos. Welcome to the Wurlie and Rhodes (the Hohner Pianet would be nice), If it's string machines. the original is waiting for you in the form of the Eminent/ARP Solina IV. Acoustic piano? The Piano V is there. Classic Synths? Minimoog, ARP 2600, Oberheim SEM's the sound engine of the 4 and 8-voice, Prophet 5 and VS. Then you can go modern with the Yamaha C-80, Roland Jupiter 8 and Juno, Obherhem Matrix.Then there are the 1980's Big Mothers. The dreaded Fairlight (how many of us did not DROOOOOL over that?) and a Synclavier with a twist: A new design for Arturia by one of the inventors and a Casio CZ. Play samples on the Emu Emulator II You can get the Ensoniq SQ-80 and Arturia's own Pigments. Play 'em as plugins or on their own. If you want a taste of all the V Collection instruments, go with the Analog Lab. If you are a Classic or Prog rocker, stuck on the '60's or into the 50's or all of the above, there's something here for you. And just wait until you see all the knobs, sliders and switches on the KeyLab MIDI controllers. Damn thing looks like a synthesizer in its own right
Not as well done as Arturia but a good companion is the IK Syntronik. This is a sample-based configurable player that includes the Moog Opus 3. The GUI's are not that realistic