I have always loved "Spock's Theme" from the Original Series. You know that awesome melancholy base and/or violin that starts up when Spock is having especially Vulcan moments? And now I've found it on the web! And it's downloadable! Here it is:
http://www.trekconnection.com/sounds/midi/
You don't have to download it do listen to it, but if you do d/l it, it comes in a midi file that's incredibly small ( as in 4 kilobytes!) and you can put it right into GarageBnd and start playing with its 4 tracks, effecting it in different ways, etc. But it's neat all by itself, though I don't like all the sounds in it. But I can just turn those sounds off or change them in GarageBand! It's my favorite music from Star Trek TOS.
Of course, then there's the one (Plato's Step Children) where Spock actually sings...
"Take care young ladies and value your wine
"Be watchful of young men in their velvet prime
"Deeply (gladly?) they'll swallow from your finest kegs
"Then swiftly be gone,
"Leaving bitter dregs.
"Ohhhh, oh, bitter dregs.
"With smiling faces and tender touch
"Man offers little, but asks for so much
"He loves in the breathless excitement of night
"Then leaves with your [something] in cold morning light
"Ohhh, oh, in cold morning light..."
Something like that. That was from memory.
Plato's Step Children also had TV's first interracial kiss, between Kirk and Uhura. Later, in the '70's Nichelle Nichols (Uhura) kissed my dad! My dad said she was pretty sweet.