Judge Dredd was my first rebuy...mostly because of opportunity and cost. Reluctantly traded the first towards CV. Second one popped up for cheap ($800, which was cheap even back then) and was nicer. Unfortunately that one also reluctantly went in a large trade deal for my X-Men. Miss it, but no regrets. Wouldn't be too surprised to have a third someday.
Also bought Stern Star Trek twice. First was NIB Premium. Traded it for IM + NF, which was a good deal, but I regretted letting it go almost immediately. Eventually traded for a barely used Pro. No regrets "downgrading", and I like the artwork way better.
Just a couple days ago I did it again. This time Spider-Man. Had a routed original, but let it go as I really wanted a mint one, plus the vault was just coming out at the time and had me interested. Side note, it was traded for my replacement ST. Well I was finally able to replace it, this time with a barely used Vault. Bolting this one to the floor!