To use self-appraisals in the performance-appraisal process or not? That question has been debated for years (and will continue to be for many more). But Sharyln (a.k.a. HR Bartender) makes one of the most convincing arguments for using self-appraisals I have read. How an employee rates himself/herself and the specific examples to justify that rating can give you a much greater understanding of that employee. Read Sharyln's post here.
She also mentions that some people think performance appraisals ought to go the way of the typewriter and punch card. I am in that camp. We might (might) be able to fix the system by pouring in a lot of work and reinventing nearly every aspect of how we do appraisals. Would we do this for any other failing system? No. We would set it aside and start over.
All that said, the vast majority of you will have to do evaluations and Sharlyn's suggestions will help a lot.