Personally id go with the chevelle ss, nova ss or elco ss route. Just depends on what youre trying to do (having a decent nice whip right now/not really looking to do any restoration through the years vs. Trying to do some restoration and having a really nice whip down the line). With that said, any car you choose will eventually be somewhat a money pit.
Chevelle is cream of the crop, very expensive especially if you buy somewhat restored. Personally, i like the late 60's to early 70's models.
Nova ss's are nice, kind of a poor mans chevelle, but still really nice/respectable. Youll have to flip through the years of novas to see what kind of body frame floats your boat. Compared to chevlles, novas are very affordable, you can probably find one that is in really good shaoe and still have some money leftover to do what you want with.
Elco's. Great car, but they dont float everybodys boat. Personally i like the mid 70s to mid 80s models, theyre more sportier and less of a whale of a car than other years. These are cheaper cars, you can buy one thats pretty close to being restored, and still have money left over.