My favorite temperature sensor is the DS18B20 which connects to a one-wire bus. They are available in a transistor-sized package for board mounting or in a waterproof metal tube. They cost around $2 each and you can string multiple sensors together on a long wire with just three conductors. The signal is digital so there's no issues with random noise on the wire and they have proven to be exceptionally reliable.
I use them to monitor every pipe on the boiler system, in-flow and out-flow temperature; the fridge and freezer operation; the hot tub and some external temperatures.
Even though the DS18B20 is more reliable than the DHT11/22 sensors it may still glitch:
An overview of the many sensors I've experimented with for home automation including my favorite under-floor strain gauge, through all the usual PIR, beam and contact sensors to some more esoteric devices like an 8x8 thermal camera.
Bluetooth sensing for home automation is a great proxy for people counting as it can detect and locate each cellphone in the house. iBeacons attached to tools, cars and pets can provide a 'find my anything' feature too.
Having at least one light sensor is critical for any home automation system that controls lightng. Lights need to be turned on when it's dark not at specific times of day, especially here in Seattle when it can be dark and cloudy at any time of day.
Microwave doppler sensors can be found in some alarm sensors but there are also available very cheaply as a separate component. They offer exceptional range but suffer from false triggers requiring a probailistic approach to people sensing.