The radio in my 78' FJ-40 Landcruiser...well, actually I regret selling the whole truck! Hmmm, audio gear? I have had attachments to various pieces of gear, but no "regrets". Some good memories of fine gear from the past though: Wright Mono 10 amps, Mesa Baron amp, Silverline SR17 speakers (I've had three different pairs just because I missed the previous one I'd sold), Klipsch LaScalas (sold one pair, still have a pair that is in storage...temporarily). You move on, not necessarily always upward, but hopefully ever evolving and always involving you with the music we all love.
...I do not want what I have not got.
Marco