I tend to be shooting landscapes (and, if metering manually, they tend to be tricky ones at that) so I try to meter for a mid point usually. TBH one of my favourite things about digital (I had a 35mm Pentax MZ-50 and learned more using digital for a week than I did using film for six months) is I can try it, check the histogram and the review image, and re-shoot if I need to.
For example in this one...
I metered off the red bits of the clouds. And in the one below I metered off the clouds that are just to the left of the tree in the middle as they represent the closest to a mid-brightness that I could find.
