Is it acceptable, or advisable, to include self-assessed ratings of your skills on your CV I am in the process of updating my CV. Since I often get labeled as "the bioinformatician" I get to play with many different languages and technologies, and similarly what people expect from a bioinformatician varies from person to person. So I figured it would be a good idea to indicate how much I feel I know in respective fields/languages.

Inspired by this question, I came to wonder whether or not its acceptable to have self-assessed ratings of your technical skills, such as: proficiency programming languages, familiarity with relevant software etc. 

My own feeling is that such ratings are useful to indicate what you feel most confident or comfortable with. It would also be useful to show any potential future employer the level of competence you have in different fields. If you think about it a bit, it is common to have some type of rating for the languages one speaks, so I think an analogue to programming language proficiency should not be that alienating.

On the other hand there is the risk of rendering your CV like, as a friend of mine put it, a role-playing game character sheet. 

Is it common to have such ratings on skills? Are there any potential problems with it? 

Edit: What I was thinking is a small listing something like:
What scale do you intend to rate yourself on?  Maybe that sounds like a silly riposte, but that's a serious issue.  If you say you're proficient in Java, how does the person reading the CV know what on earth you mean (assuming they're willing to take your word for it).  I would be much more inclined to focus on what experience you have with a language (I have X many years of Java programming experience, I've done such and such projects), since that's actually something which people understand the meaning of.  You also don't necessarily need to cover this in a lot of detail in your CV, since if you're applying for a job where these skills are relevant, you can mention it in your cover letter.

EDIT: In response to the proposal of using stars or a 0-5 rating:  DON'T DO IT!  If you want to write "I'm proficient in Java and have some experience in C" that's harmless but won't make too much of a positive impression either without some more concrete information.  The stars will make you look eccentric at best, and lunatic at worst.  I know that some times the usual convention about how to do things seem constraining and silly, but if you've never seen something on a CV before (and I've never seen giving yourself numerical ratings on an unknown scale), there's probably a good reason.