This is such a tough question because I've carefully selected the guns I have over a 40 year timespan. None were inherited but they all mean a lot to me since I put so much thought into each one. Sure there have been a few disappointments but most worked well out of the box and continue to please even today such as my Colt Series '70 45ACP, Ruger Mark I, S&W Model 19 and a DWM/Mauser FrankenLuger bought in the 1970s; Star PD, Ruger Mark II, S&W Model 66 and FM Hi-Power from the '80s; and a few others. Of those I carried the 1911 with me almost everywhere I went and still do.
But I have to say the one that would be hardest to part with is my 1941 BYF Luger. About 15 years ago a buddy was leaving town and asked if I was interested in buying his Luger. At the time I liked Lugers with wooden grips but these were cheap bakelite but the Luger itself was like new, hardly fired. I went ahead and bought it because the price was good and I knew I'd never be able to afford one in this condition. I'd say it has less than 100 rounds and I've never fired it myself (though have many thousand rounds through my mixed parts Luger).
Well as many of you have figured out the ugly duckling has turned into a beautiful black swan and today 1941 and 1942 BYF "Black Widows" command a higher price than ones with wood stocks. Seems over the years people ripped off the cheap stocks and put on wood so now the bakelite is rare. Anyway, don't know exactly what she's worth but here she is!