I personally need to have someone "making" me stretch, telling me what to do (or I don't stretch at all, I find it tedious and boring to do completely alone).
To fill that need, I have found yoga classes in my area that cost anywhere from $4-7 per class and attend those 1-2 times a week.
I'm doing the Bikram series at home with the audio CDs (there is also a book
that explains the poses in more detail, plus a one-page quick reference guide to the poses here
) 1 or 2 times a week. I shoot for 3 total yoga sessions a week, I usually get a minimum of 2 in for sure.
If you have stuff that needs specific work (ie. calves), make it a part of your warm-up.
If you try yoga, make sure you give several different styles and teachers a chance.