Best book (for a Discworld virgin)

I'm looking to buy a Discworld book for someone who has never read anything from the series, so I started thinking about my favourite Pratchett book. Mort definitely comes to mind, because I think Death is a wonderful character, plus it has the advantage of being a self-contained story so that my friend won't become too confused with all the side-characters. Small Gods is another one for the same reason, plus it's quite philosophical which is a plus in this case (he's studying philosophy ). Other suggestions? Or do you have a personal top 5?

For a virgin I would get Hogswatch.

Good idea, fits with the period too (Christmas and all that).

Yep, I'm a genius.

Thief of Time or maybe Pyramids? IIRC they don't contain too much references to the rest of the world and Ankh Morpork only plays a small part in the plots. I would recommend the Wee Free Men series but I feel that the reader should know some basics about Grandma Weatherwax before this though.

EDIT: While I do agree that death is a wonderful character, I would actually not recommend a book so heavily dependent on him for a newcomer. Let the suspense and interest about his persona build up before introducing books that revolves around him. I would say the same about Ankh Morpork.

Hah, I shoulda known that there'd be a Discworld group on here somewhere. Found it at last!

I came really late to the series - Thud! was the first book I read. I really loved it, have been hooked on Discworld ever since, and still have a soft spot for Vimes and his motley crew. It comes with a health warning though: its one of Pratchett's more serious books, and though there's still loads of humour, its not quite as laugh-a-minute as some other books in the series. Personally, though, that's one of the things I liked about it.

Oh, and the girls' night out story arc is horrible. Your friend has my permission to have selective blindness when it comes to reading through that part of the book.

EDIT: While I do agree that death is a wonderful character, I would actually not recommend a book so heavily dependent on him for a newcomer. Let the suspense and interest about his persona build up before introducing books that revolves around him. I would say the same about Ankh Morpork.

And what if I do want to introduce him to Ankh Morpork? The Colour of Magic isn't such a great choice I think (it's not one of the best books, but I'm basing myself on memory now). Guards! Guards! maybe?

And Colonel Cleg McLeg, welcome to our little group!

Dammit! Now you've got me rummaging through my collection. Hmm lets see... Oh, seems like I'm missing Thud.

Anyway, here's a couple of titles in no particular order that deals with Ankh-Morpork. Some of them may have heavy references to other characters, I can't really remember the details.

I think these two have little reference to previous books.

Spoiler Alert, click show to read: 

The Truth
Going Postal

All these involve the Watch and Vimes so I'm not really sure how good starters these are, though I guess Guards! Guards! if you want to introduce Vimes properly. On the other hand, I never read Discworld in any kind of order and when I found out there were books that dealt with things that had happened earlier on the timeline, it only spurred my interest more.

Spoiler Alert, click show to read: 

Thud
Feet of Clay
Guards! Guards!
Night Watch
The Fifth Elephant (my personal favorite dealing with Vimes)

I must admit, I didn't really like Vimes when I first encountered him but I've grown fond of him over time.

I've intentionally left out the books that deals with the witches and magicians. Not really that exciting unless you know the world to begin with in my opinion.

Hah, I did the same but on Wikipedia and in the bookstore . Reminded me of the fact that I should start re-reading them all. Thanks for all the suggestions, I'll think about them. I've still got one or two weeks before his birthday, so there no rush to decide.