The Colt Delta came in blue and stainless, and in regular and enhanced versions of each metal. There was also a Gold Cup version and a few others.
The best one would probably be an enhanced version, as it already has most of the mods anyone would do straight from the factory. The factory also does a good job. It's not cobbled together.
I bought a normal blued one, used for $540 a few months ago. That was a good price. I haven't seen one for less than $500 and most go in the 7's. Gold Cups will fetch a grand or so.
While it's a nice enough gun for what I payed for it, it's not good enough to be calling for too much more IMO. I mean it's a Colt and a high quality gun and all, but the high prices are a reflection of it's collectability. They've started to become somewhat of a collector/cult piece. I think if you get one now, you'll be getting in on the lower floors of a good investment if you keep it for a while.
Two things working in your favor is that most 10mm don't get shot to death much by most folks because of ammo cost. Also it's hard to sell a 10mm unless it's priced right. The market is small, so have patience and a good deal will show up soon enough.
The difficult to sell thing goes both ways though. If you think you might sell it later on, you might loose money on a Witness or Smith and Wesson. The Colts are holding value, so getting a Delta is lower risk.
www.pistolsmith.com has a forum with great info on the 10mm. Lots to be learned there.
I've owned a 1006 as well, and if you're looking for a utilitarian auto to shoot alot out of, the S&Ws are hard to beat. The 610 revolver is probably the best 10mm going for versatility, as you can shoot 40SW out of it as well. Glocks and the Witness are out there as well, so there's plenty of platforms to choose from. They are all different enough that it's really a good selection.
Ross