My 2 favorites, the 1 of 600 LW Colt CC in 38 super, i stole for under $500 new in the box, and is now impossible to find, and the H&K P7 M13. New in the box it was $1100 in 1990 when normal big names were half that, and at the time was considered the worlds most expensive off the shelf pistol. If you ever get the chance to own one, you'll find its quality and accuracy to be undeniable. I recently wanted to aquire another and when I went looking I was speachless to find that poor examples are fetching $2500, and for an unfired example with box and materials they bring as much as $6-7000, ultimatley topping at $10-12000 for the rare .40 cal model in Nickel.
The P7 I have to say aside from the quality is truly the safest handgun you could ever carry, as theres not a degenerate on earth that knows how it works. I used to make $100 bets with people hand over the gun (unloaded and checked) and would agree to pay the hundred if I could snatch it from there hand before the could dry fire it, and i'd win 90% of the time. Most amazing is that even my cop friends had no clue. The safety is that if someone gets it from you, your odds of getting shot with your own weapon are pretty close to nil.