Arisia or Boskone for a taste of Winter and to see our East Coast friends. Consonance in March in the Silicon Valley. Conchord in the LA area. Loscon in the LA area. I'm also going to be running filk for the 2002 Westercon.
Some trends are technology-driven.
Relatively cheap costs for publishing by cassette or CD have also allowed commercial filk recordings, which in turn has encouraged writing songs to original tunes because people are able to learn the tunes from recordings rather than having to puzzle them out from sheet music. I'm sure that the Web and the various pieces of software allowing using to be posted on webpages will have similarly far-reaching effects. Back in the 1960s, filk was the common heritage of all trufen. Nowadays it's often considered a fringe activity. I don't think this is because most fen have gotten less musical.