I use the MaryKay daily face routine: Wash with the cleanser, use the day serum, use moisturizer. Then night: wash, night serum, moisterizer.
I used to do nothing, but my skin has been getting dryer and dryer. I went to a MK party and didn't buy anything.
Then I went on ebay and bought the 4 product set for $30 (instead of the $90+ the MK rep was charging).
Cetaphil made me break out, which is really weird. It's highly recommended by Drs and is usually the least expensive option too.
ETA: I forgot to say that I LOVE the way my skin feels and looks now. Its a huge difference!