I have two keyboards (both in varying degrees of destruction), and a set of VSTis, some free, most not. As pretty much all of my work can be classed as “MIDI Mockups” of how something would sound when played by an orchestra, all of my kit revolves around samplers and MIDI-capable sequencer(s):

Monitoring:

Alesis M1 Active Mk 2s
Tannoy Reveal 601 Passive
AKG K271 (55 Ohm)
AKG 701

Input:

Fatar Studiologic SL-990 MIDI Keyboard
Roland Fantom-S Workstation
Korg padKontrol
Soundcraft Compact 10
Zoom H2

Software:

Cakewalk Music Creator 2002
Cubase 5 Studio
Edirol Orchestral SoftSynth
East West Quantum Leap Symphonic Platinum Plus
East West Quantum Leap Ra
East West Quantum Leap Symphonic Choirs
Komplete 6
Kore 2
Independence Pro
Vienna Symphonic Library Woodwinds I, Percussion I & Brass I
8Dio Violins

My main machine is a fairly bog-standard PC based off a mid-range Intel i5 of some sort, with 8GiB of RAM. Soundcard is an Emu 1212M. All samples have since been relocated to a 700GiB SSD to cure loading issues, and it performs pretty damned well at being a WORM drive, which is essentially what sample-data needs.