Actually, I would extend the concept further. But for the purposes of this thread I am willing to narrow it down to the time of the day. I suppose the concept of a raga was evolved with precisely this same idea. Some of Anup Jalota's bhajans seem tailor-made for waking up to. In fact, Vividh Bharati had the right idea when they used to have early morning programs which were bhajan renditions by popular singers.
Mornings are the most pristine time of the day.
An early ablution and devotional music somehow bring that taste of tulsi, the smell of the earth moistened by dew, the kiss of the morning sun - gentle, yet invigorating. I vote for light, but fast-paced music. Yesudas would be good, so would some of the newer singers - Amit Kumar and Suresh Wadkar in particular. Manna Dey would be good too, but not the heavily classical stuff. At 9am in the morning, I want songs I can sing with, not songs which give me an inferiority complex.