The only guitar I ever really regretted selling was my first modified 1973 Les Paul Deluxe.
I sold it to pay for another guitar. Actually the guitar I bought with the money while being a FAR superior guitar (1981 BC Rich Bich-6) didn't get along with me. I really hated the neck and eventually sold it.
I can't be too upset about selling off the Deluxe. I made a lot of money on the flip and I ended up buying a different one that I actually like much more.
Ironically I sold the Marshall Lead 12 Microstack pictured with my Deluxe. I bought it for a great price. Eventually I wanted to dump the solid state circuitry in the head, and replace it with a nice tube amp. Deftone made me want to do this! Anyway, I posted the amp on Craigslist for a silly price wondering if I could get it. Eventually someone emailed me and told me he was interested. He asked if I could take off $50.00, which still would have been a great profit for me. I wouldn't budge. Then he asked if I could go $25.00 lower. My response was no. A few hours later he told me that he'd do the price I wanted. I was actually a bit hard for me. I really had no personal attachment to it, I really only had the amp for a month or so, but I really hated to sell it. I really thought, and still think gutting out the head and throwing a simple tube amp in there would make for a tremendously cool and unique guitar amp. Well he met my price, I made around a 58% profit on it. Still I was hoping I could talk the buyer out of it. The rig was great, all original, no scratches, no tears, no dents and all original. It sounded pretty good when I plugged my guitar to my iPhone Amplitube. There was some unwelcome feedback, but for what it is, I was very happy with it, especially how I got it. Anyway when I spoke to the buyer for time/place deal I'm telling him how many far superior amps are being sold on Craigslist that day. I couldn't change his mind. Oh well, it worked out quite phenomenally for me.
I went from a VOX AC4TV mini and a 10+ year old Pignose I haven't really played in years. I took the proceeds from those sales and added $40.00 to get the above Marshall Microstack. Soon after sold that for just a ridiculous profit and got my current rig. Oh, my rig is an Egnater Rebel 20 and a homemade (not by me, but built like a tank) cabinet that came with a new 15" Jenson MOD15-200
Actually the BIGGEST guitar gear regret I have was selling my "baby" Swart amp. That was really something very special.
If I sell off my current rig and pedals, I have an additional pedal are from a company called Damage Control that has been discontinued so the folk at Damage Control people can go work with Strymon. The pedal is a Damage Control Solid Metal.
With that, I'm actually in good shape to pull it off for a used one. Dang it, I'm pretty happy now. I really want a Strymon Timeline in the worst possible way, so there's a lot of saving to make that happen .
I've just taken some sleeping meds so if it reads like I'm wasted, I'm probably wasted.
I have some regrets (generally guitars that I had for 5+ years), but each time I parted with a guitar, I eventually ended up with a guitar I liked even more.
I always figure that somebody else is enjoying a guitar that had lost its luster with me.
I'll probably miss my Jetglow Rickenbacker 350v63 the most (more for its looks than for how it played), but it was traded in for my Heritage Cherryburst LP Traditional that is my current favorite guitar.
Back in the 80's, I traded a 60's era tobacco sunburst Gibson 345 and a blonde Fender Super Reverb with Jensen speakers and traded them away for items worth far less.
Traded off a 70's era yellowed-with-age white Gibson Les Paul Custom that was supposedly owned by Paul Kossof for stuff worth far less. I have done some stupid. Bet you will have a hard time beating that. I most definitely regret letting those guitars and amp go.
I've been fairly good about only selling guitars I wasn't using. My only real regret was trading my Ovation Glenn Campbell for a Guild D-25. My father gave me the ovation and I never should have sold it...
sold my first guitar, a Chester Les Paul in creme, and regretted it. Got it back two years ago
Sold a Fender Japan Strat and regretted it, I have it back, too It's a benefit when you sell gear to friends and relatives.
Sorry no pics, I'm at work