The Rats in the Walls and The Call of Cthulhu were both good. I'm currently reading At the Mountains of Madness and it's a fantastic read so far. I'd start with Rats or another shorter one for your first time out. The vibe of that story reminded me quite a bit of Poe's House of Usher.
-------------------- "Thou shalt not be afraid for the terror by night; nor for the arrow that flieth by day;
Nor for the pestilence that walketh in darkness; nor for the destruction that wasteth at noonday." -Psalms 91:5-6