There are some items that I lament selling because I now realize they were unique and I'll probably (or defiently) never be able to replace them. I still have pictures of much of what I had. These images haunt me.
[FYI- I apologize in advance if this sounds too EMO.]
Case in point...
Several years ago, I was unable to attend Emerald City Comic Con, but found someone who was going and took some books to have signed for me. Several of those were Lady Death variants that I requested to have Brian Pulido sign. I had them graded because they were so very prized. One even came back as Gem Mint 10.0! A few months later, I had to sell them on eBay to pay the bills.
Before that, I had sent some of the chromium Lady Death cards for Chaos! Comics to be signed. They represented the covers for the original Lady Death mini series. When they were returned, they had the signatures of Brian Pulido, Jason Jensen and Stephen Hughes. I was very greatful that my request had been granted and it wasn't until after Stephen Hughes passing that I began to regret selling them only a few years prior.
When I was in high school, I had decided to have a complete collection of Uncanny X-Men comics starting from issue #200. I worked on this goal for several years after high school until I received a collection which contained several issues prior to #200. I changed my goal to collecting everything from #100 at that point. I had several of the key issues up until I stopped collecting around the time of the Age of Apocalypse. I am proud to say that I still have the issues I had signed by John Romita, Jr. and Fabian Niceza the one time they came to the Portland Comic Book Show.
As many male members of my generation, I grew-up with Star Wars action figures. I had a large collection of them, and several of the vehicles. I didn't keep them in excellent condition, but they did survive to my adulthood. The last time I had a table at the Portland Comic Book Show was the last I saw of most of them. I still have a few vehicles (including a Millenium Falcon) stored away in my parent's attic.
At my last position (as of this original posting), I began collecting the vinyl Muggs figures. I had them all displayed at my desk. When I left, they went with me... neatly packed into 3 boxes. Within a month, they were all sold on eBay.