After all these years, StarCraft is still the best RTS choice by fans, pc magazines around the world.  There are plenty of replay values, thanks to Star Editor.  Better yet, it isn't that complicated either unlike other game's editor.  You could make your own custom campaigns, and custom maps very easily.  If you don't want to, you could download custom maps from blizzard.com.  I just hope Blizzard make few more custom campaigns and put them on their website for downloading.  StarCraft: Battle Chest has original StarCraft, StarCraft expansion set: Brood War and two separate guide for each game for you to enjoy the world of StarCraft.  ... Go buy it now!  You'll be glad that you did.