Time for Congressional term limits?

President Obama can only serve 8 years

Some are calling President Obama the greatest President ever. I think it's way too early to make such a statement. However, if Obama does become the greatest President ever, he can still only serve the US as President for 8 years, or two terms.

However, many in Congress have been in Congress for decades, as there are no term limits. Is that really fair?

Should there be term limits in Congress? Or, should Presidents be able to serve for as long as the people will elect them?