Id rather have the feeling of being in a dark, stormy, & rainy atmosphere rather than a sunny day. Just my opinion, though.
I like both. On sunny days I feel really happy and active and on dark days I feel cozy and sleepy, in a good way. I love to just put candles on and read a book or watch a movie. I usually ride my bike around on sunny days.
The sound and feeling of it is just so amazing and freeing. I also end up listening to this when I can't fall asleep: http://www.rainymood.com. It's so relaxing and calming.