In response to this call for ideas on rss legal feeds, and a prompt from Ernie, here's a few unrefined suggestions, in no particular order:

• Appellate Court Dockets and Opinions: to allow tracking of new filings; filings in particular cases; and issuance of new opinions. These should be primary source feeds (i.e. produced by the courts themselves either as part of the outgoing stream of data from case management systems or from weblog publishing systems). Deployment could start with the highest courts of last resort (US Supreme Court, Federal Appeals Courts, State COLR). An alternate approach may be to enable rss feeds for highly-watched cases. Most appellate courts are familiar with the benefits of enabling better information flow for cases of great public interest.
• Trackback/Comments for Appellate Court Opinions
: For the scholar, lawyer, and citizen, the Web is fertile ground to study the reaction, commentary, and impact a particular decision has on various parts of the community. I'd like to subscribe to a single feed, that, through some automatic mechanism, collects new citations and commentary regarding, say, Eldred v. Ashcroft. This is not intended to replace the services lawyers use to make sure cases are still good law (Shephard's, KeyCite), but rather as a more robust current awareness tool. NOTE: Trackback/comments would also be interesting to apply to newly-minted laws and regulations.
• Court rule changes: notification and current awareness of recent and upcoming changes to court rules. Primary source feeds. Deployment could start with the highest courts of last resort.
• Topical court feeds: this is more tricky, because it would likely depend on secondary sources (i.e., webloggers, academics, law reviews, etc.) developing a reliable "voice" in a particular area. Not quite government RSS, but the secondary sources would rely on the primary public information feeds. Some courts could take my approach, (WV Supreme Court), and deploy straightforward topical feeds like: civil, criminal, family, etc.
• Legislation: Newly introduced bills feed, together with feeds per bill/resolution number, containing legislative event items and links to full text. This could be deployed in state and federal legislative bodies. (Even if the government didn't do this, I could see a great use for this service being produced by lobbying and political organizations who have highly focused and time sensitive topics to cover. A great example of this approach is the Consensus at Lawyerpoint weblog, "Being a true account of the undertakings of the Broadcast Protection Discussion Group" and its associated rss feed.) Alternatively, (or additionally), feeds could be organized to contain the event items of a particular committee or subcommittee (Senate Judiciary hearing schedule - witnesses to appear, etc). With links to Congressional Record text of testimony?
• Regulatory activities: Newly introduced regs, and a separate feed with event item tracking per regulatory series, and links to appropriate full text at each event item. Basically an RSSified Federal Register
• Executive Orders and AppointmentsText of new executive orders, when issued. Separate items for executive appointments, as introduced.
• Election Returns: Why not? And while we're at it, throw in new filings for office.
• and the rest . . .Professional licensing history, per license number; administrative claims dockets; economic and employment data; census data; weather and space data; emergency warnings and threat awareness.

By the way, Ernie has a very thought-provoking post today about reputation systems in the legal profession.