Well they may not be for everyone but I've enjoyed building these kits since I've gotten back into the hobby the last two years.....
Monogram/Revell Boss 302 or 429 '70 Mustang (wouldn't mind doing a Mach 1 either)
AMT '65 Pontiac Bonneville or 2+2 (basic AMT kit that assembles nicely)
Monogram '69 GTO (impressive looking body)
Monogram Malibu SS-454 (like the larger 1/24 scale)
AMT '70 Monte Carlo (despite a few challenges)
AMT '66 Buick Wildcat (another basic AMT kit)
Monogram Turbo Trans Am (looks great with the t-tops)
Revell '66 GTO (one of the most detailed kits I've done so far)
AMT '69 Buick Riviera (molded in chassis detail but I like taking the time to brush paint those types)
Revell '77 Monte Carlo (snap kit but a very nicely detailed kit of a subject I greatly admire)
In my collection I've yet to build the Revell '68-'69 Chevelle kits, and the Revell '69 Nova all of which are supposed to be great kits. I also have a number of the vintage Johan Cadillac models which I hope to be doing soon so that list could change.