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These are all .scms that you should play single-player using Map Settings.  None of them have sound files (I'm not that hardcore) but on the plus side, that means they're all pretty small files.  Most can be played with either Brood War or standard StarCraft.

Campaign Missions:

Relics of the Xel'Naga:  An eight-mission campaign, including five Protoss missions and three Zerg missions.  This campaign is now complete.

Legacy of Fenix:  Four missions dealing with Fenix's history as a Protoss warrior.  This is in the works.

The Infestation:  A six-mission campaign that follows Ghost Team Omega and the Dark Templar Ashtar as they defeat a Zerg plot.  This is also a work in progress.  Will require Brood War.

Stand-Alone Missions:

Special Forces:  An elite team of Ghosts breaks into the installation of a Sons of Korhal general.

Lost Templar:  One of my first missions.  Zeratul returns to Char to rescue the Dark Templar that remained there.

Holocaust on Aiur:  The Protoss resort to nuclear weapons to contain the Zerg on Aiur, and Ghost Team Omega gets the job.