The ones crossed out are the ones I own. The ones with a star are ones I have read, but don't own my own copy of.
The Colour of Magic
The Light Fantastic
*Equal Rites
*Mort
Sourcery
*Wyrd Sisters
Pyramids
*Guards! Guards!
Eric
Moving Pictures
Reaper Man
*Witches Abroad
Small Gods
*Lords and Ladies
Men at Arms
Soul Music
Interesting Times
*Maskerade
*Feet of Clay
Hogfather
*Jingo
The Last Continent
*Carpe Jugulum
The Fifth Elephant
The Truth
Thief of Time
The Last Hero
Amazing Maurice and his Educated Rodents
Night Watch
The Wee Free Men
Monstrous Regiment
A Hat Full of Sky
Going Postal
Thud!
Wintersmith
Making Money
Unseen Academicals
This is mainly for future reference. I turn 23 in April and I'm trying to collect all of the fancy black cover Discworld books.
For example: