Much-augmented BibTeX replacement for BibLaTeX users
The biblatex package by Philipp Lehman is becoming the definitive citation management tool for LaTeX users. Biblatex has relied on the venerable BibTeX program only for sorting and generating a very generic .bbl file without any formatting instruction. Everything else is taken care of by biblatex, which provides a powerful and flexible macro interface for authors of citation styles.
Biber offers a large superset of BibTeX functionality for BibLaTeX users. In addition it offers full UTF-8 (Unicode 6.0) capabilities, fully customisable sorting, output to GraphViz to help visualise complex crossrefs, support for remote data sources, structural validation of the data against the (customisable) data model, and a lot more.