Yuri's Revenge never gets old - it's just the right balance of RTS with a bit more of an arcadey feel. Sadly I missed the original Starcraft train (finished Starcraft II), but one of these days I'm going to sit down and work my way through it.
The story still holds up really well. Plus if you can't deal with the classic graphics there is StarCraft remastered.
The story still holds up really well. Plus if you can't deal with the classic graphics there is StarCraft remastered.