Originally Posted by Nesacat
Alternatively, all his stories are available online and you could read a few to see if you'd like to go ahead and pick up the books.
Call of Cthulhu is a good place to start and so is The Cats of Ulthar, but I'm very biased here. The others that are good are rather long ... At the Mountains of Madness, Shadows Over Innsmouth ... etc.
Whichever you choose to begin with ... enjoy.
I agree with your suggestions, although I think that At the Mountains of Madness
may be an acquired taste and should be read after you are already hooked.
The first HPL story that I read myself was "The Colour Out of Space", and even now, 21 years later, I still find it vaguely unsettling if not scary.