Mplc, there's alot to be said for owning a Vette, power, performance, prestige, resale, dependability etc. But in some locations, they are as common as Mustangs.
Where as "flying under the radar" in a car that you seldom see offers a certain amount of prestige and satisfaction since very few people know what it is, and think it's something special. (Which it is!)
I too have always enjoyed owning alot of cars, but essentially I went from a Viper GTS, to my '04 Crossfire 6 spd. and I haven't missed the power difference one bit. Because, as you said, I never used it, even though it was nice knowing it was there. Actually, I still own the Viper, but I haven't touched it since the Crossfire showed up over two years ago. I could sell it tomorrow and not miss it. Not because I didn't like it, but it's more of a "been there done that" sort of thing, and it's time to move on.
If you're concerned about depreciation, and resale, then I would say find a used SRT6 roadster. I believe they will hold their value better than a Limited, or a Base car. Also, I don't think that you would notice the 1/2 a second difference in the 1/4 mile performance between it and your Vette.
If you have read many posts hear on this site, it should be very clear that this car creates alot of passion amongst its owners, and I for one feel the same way. After 2 years with this car, I still enjoy it as much as I did when I first bought it, and I can only say that about one other car. That's why for me, I think it's a keeper.
Good Luck with what ever you decide to do, but I don't think that you will ever regret owning a Crossfire.