On his Facebook page, Rep. Jim Matheson (D-UT04), my representative, just announced he will not seek re-election.
Matheson has always been a pain-in-the-ass Blue Dog, and one of the least dependable Democrats to support the party line on controversial issues. However, my disgust with him ebbed significantly in 2012, when he defeated teabagger Mia Love in a horrendously gerrymandered district with Utah's favorite adopted-son Mitt Romney at the top of the ticket. Plain and simple, the dude could win elections consistently in one of the most Republican-friendly districts in the nation. He is going to be hard-as-hell to replace from that perspective.
Off the top of my head, former Salt Lake County Mayor Peter Corroon (Howard Dean's cousin) and current Salt Lake County Mayor Ben McAdams (an LDS, progressive, Democratic Party rising star) are the only two names that come to mind that would have any chance whatsoever of holding this seat. No word on whether either is interested.