I don't so much as have a favourite colour but favourite set of colours or tones. For me they are beige, brown and an earthy green. My second favourite is teal/aqua and silver, I also like peachy pink. Since these three colours (green, aqua and peach) are my favourite and compliment each other well they have become my overall colour scheme I use on the site in forums.
As a solid colour however I often favour green over all the others