My company makes employees set goals like you are referring to yearly but they are pretty much BS and everyone knows it.
However, I do set personal goals for each year around Christmas time. These aren't necessarily around work but areas in life I want to improve on or make some sort of progress in. These aren't new years resolutions like everyone makes but then makes no effort to achieve.
I usually do 5 to 6 a year and my goals are written out and most importantly quantitatively measurable. At the same time, before the new year I sketch out a rough timeline (again in writing) of each portion of each goal, what I need to achieve it, step by step etc. This has proven amazingly effectively over the past 3 years, getting me off my ass and accomplishing things that most people put off continually.
For example, one of my goals this year was to start a side business in x field with at least y amount of revenue in 2010. I did this successfully and learned a ton of stuff about starting a business, dealing with accountants, lawyers, business law, etc. Even better its already profitable.
To take an example of most common New Year's goal, go to the gym more and lose weight. Yeh, that is ill defined and the person will give up after gym visit 3.
The way I would phrase this one is along the lines of the specific outcomes I want. I mean you go to the gym as a means to an end, not to an end in of itself. So I would say my goal in 2011 is to lose 20 pounds, up my bench press by 30 lbs, and be able to run a 10 min mile for example. Then I would timeline this out (leaving it open for adjustments since shit happens and you want to experiment) such as by June 1, 2011 have lost 10 lbs, be able to do a 13 min mile etc.
Basically these have really helped me out and I'm already planning my goals for next year.