Steam. When Relic developed the original game those many years ago, the WWII setting and RTS scene were both feeling tired, but Company of Heroes delivered a fresh take on the aging genre and delivered a graphically gorgeous experience that still holds up. You can own the intense, immense campaign now for $2.
If you're willing to spend more than a gallon of gas for tens of hours of refined RTS entertainment, the original game is bundled with expansion Opposing Fronts for $6, and with the Opposing Fronts and Tales of Valor expansions for $10. If you have any interest in the RTS genre -- even if the WWII setting is a bit of a turn off -- don't miss out on Company of Heroes for $2.