Well let's see. These are the ones I used most frequently over the years.
FS Unknown mid 80s version (Mac LCIII Moterola 25mhz processor, before vid cards came out, my palm pilot has more computing power)
Tie Fighter (Moterola Starmax Mac clone, 200mhz)
Warbirds (PII 233mhz with no video card)
X-Wing (PII 233Mhz, no card)
CFS1 (PII 233mhz no video card)
XWing vs Tie Fighter (PII 233mhz, ATI Radeon PCI 32mb)
XWing Alliance (PII 233mhz, ATI Radeon PCI 32mb)
FS2002 (Duron 950, Geforce2 MX400)
CFS2 (Same system as FS2k2)
CFS3 (Duron 950, Geforce FX5200)
FS2004 (Duron 950, GF FX5200)
Oh i forgot my X-Wing and TIE which managed to wreck 3 joysticks before i got my first decent one