Like many here probably I've got music on all formats (tapes,cd, records, etc). But given the technology of today, I think mp3 (ripped at 320k from cd) is the way to go. I keep an 8gig iPod touch freshly filled with music (it also has orb and last.fm support via wifi).
And I keep a vestax turntable and a vintage NAD stereo system for the "obsolete" formats also.
What's your poison?