I have no regrets about any equipment I have sold... Now regrets about equipment that I have bought... THAT is a different story.
I certainly regret selling my "looks like new" Technics SL-1000 MK II turntable set up, especially considering what I sold it for and what I see people are now asking.
Fortunately, sometime later I got an SP-10 MK II on an excellent broadcast base. . .
And I would wish even more that I hadn't sold my Tannoy System 12 DMT II studio monitors, except that recently I got a decent deal on a NOS pair of System 15s.
I didn't think I'd ever say this, but, other than a Grace 707 arm (once I pay off some debts), I think I'll only be buying LPs, CDs and SACDs for the foreseeable future.
Happy listening all!