I know I would like
Trypticon
and maybe Scorponok, preferably Black Zarak
All combiners, I have most of these already but I crave mint versions. A complete mint Computron is my most wanted
Targetmasters and Headmasters but after everything above.
I think reissues are good for me personally. I was never prepared to pay big dollars on originals. On the rare occasion I might it would be for something that has a sort of sentiment attached to it, sort of like a holy grail.
Encores appeal to me because of the packaging and box art, unlike the book style takara reissues, or even the hasbro commemorative editions. Reissues may lower the inflated value of some G1 figures, but if the figure itself is mint and complete it would still fetch a good price. Its the substandard figures that people on ebay who try to pass off as excellent deserve to come down in value, and Reissues are a better sustitute.