I'm not going to limit my list to just pc, because really there's been all sorts of titles that have blown me away that were released over all sorts of platforms.
Arcade wise:
Ikari Warriors
Rastan
Punch Out
Narc
Bad Dudes
Mortal Kombat 1-3
Killer Instinct
TMNT
Mechanized Attack
Operation Wolf
Tron
POW
Wrestlewar
Outrun
Ninja Warriors
X-Men COTA
Time Killers
Street Fighter The Movie
Art Of Fighting
Samurai Showdown 1 and 4
King of Fighters 95
SF Rush
Tekken 3
Primal Rage
Nes:
Mega Man 3
Double Dragon II
Ninja Gaiden 1 and 2
Super C
Tecmo World Wrestling
Lifeforce
Super Mario 2
Shatterhand
Snes:
Super Mario World
Super Metroid
Contra III
Super Castlevania 4
Pilot Wings
Super R-Type
Gradius III
Genesis:
Altered Beast
Splatterhouse 3
Castlevania Bloodlines
ShadowDancer
Pit-Fighter
Sonic 2
Lightning Force
Jaguar:
AVP
Doom
Wolfenstein 3D
Ultra Vortek
3DO:
Way of the Warrior
Gex
Shockwave 2
Crash and Burn
Wing Commander III
Need for Speed
Road Rash
Total Eclipse
Off-World Interceptor
Star Blade
Guardian War
D
Turbografx 16/Pc-Engine:
Ninja Spirit
Splatterhouse
Street Fighter 2 Champion Edition
Galaga 90
Bonk 2
Exile
all the Neo ports on Arcade Card cd
L-Dis
Dracula X
Vasteel
AeroBlasters
Alien Crush
Raiden
32X:
Star Wars Arcade
Virtua Racing
Saturn:
Battle Monsters
Virtua Fighter 2
Dead or Alive
Panzer Dragoon 2
Shin Shinobi Den
Daytona USA
Virtua Cop 1 and 2
Shining Force III
Thunder Force V
All Japan Pro Wrestling Featuring Virtua
Fire Pro Wrestling S
Akumajou Dracula X
Radiant Silvergun
Playstation:
Ridge Racer 1 and 4
Tekken 2 and 3
Twisted Metal 1
Metal Gear Solid
Guilty Gear
Resident Evil
Dreamcast:
Giant Gram series
Sword of the Berserk
DOA 2
Giga Wing 2
Guilty Gear X
D2
RE: Code Veronica
Le Mans 24 Hours
PC:
Mega Race
Wolfenstein 3D
Quake
Quake 3
Serious Sam First Encounter
Max Payne
Carmageddon 2-3
MOH Allied Assault and Airborne
COD 2, 4 and WAW
Unreal 2
Doom 3
NFS:High Stakes
DethKarz
RTCW
Unreal Tournament 2k3
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I'm going to end it there for right now. Newer pc stuff really I'd need to give a couple more years, go back, and see if they still impress me like the stuff I listed above.