I currently have Magnepan MG12 speakers, Aragon 2004 Mk II amp, Bottlehead Foreplay 2 tube preamp with upgrades, Rega Planet, Rega Radio, with hodgepodge interconnects (MIT, Transparent Link) and Home Depot 14G halloween cable speaker wire. I am very happy with the sound but am getting the upgrade bug.

What would have a bigger impact, a DAC, a new preamp, new interconnects or none of the above? Any suggestions welcome.