Haha, I will note that you registered on this forum almost 13 years ago and this is your first post. I'd welcome you, but you were here before me!
I'd say that a 59 in very very nice condition all around but without original box with matching emd label, papers, cleaning kit and extra magazine would likely top out at $450. This is mostly because S&W made sooooo many of these pistols, the "collectible" value is not high.
I own many 1st, 2nd and 3rd Gens (including a bunch of 39's and a 59) and my opinion is simply that I would much rather own a 59 than a 459. The 459 has three upgrades -- arguably a 4th.
1) firing pin lock makes it drop safe
2) some available with ambi decock lever
3) most have fully adjustable rear sight
4) far, far less 459's/2nd Gens made
I prefer the 59 because...
1) that lock makes the 459 trigger horrendous
2) I don't like the ambi decocker at all
3) I hate the look of 2/3rd gen adjustable rear sights
4) 459 only arguably "more collectible" because fewer were made -- it is not a "better" pistol in my opinion
To be fair, it isn't simply the firing pin lock that make 2nd Gen triggers bad... it's just what S&W was making at the time. Far less human craftsmanship went in to the 2nd Gen pistols and the most obvious result is that the single action trigger break is sub-par and the long double-action trigger stroke is an abomination. This is basically across the board. Doesn't matter which 2nd Gen model -- it's trigger will pale in comparison to a 1st Gen.
If you liked the 459 that you had, I think you'll LOVE a Model 59, and the market for 59's makes that venture even better because they are a fantastic value.