Value is in the eye of the beholder....that being said...
What kind of car do you want? Can you do the work yourself?
If you are buying a total resto case (all rotten and needing everything), buy a '70 or '71. The cost of the restoration is about the same across the years and even though the early cars cost more to get into initially, they sell for a heck of a lot more at the end. The cost of the resto will far outweigh the cost of the car. This rule CANNOT be broken if you are paying for the resto! A good restoration starts at $25K, and that's cheap IMO. A rust-bucket resto will be double that. A concourse E-body resto is in the $75K to $100K range. I will have about $20K in my '72 resto, which doesn't include a lot of mods or upgrades and I'm doing all the work myself. I've also been doing this car for 2 years and this is my 3rd restoration.
If you want a driver already put together and don't care about numbers and stuff, but like the look of the e-body, buy a well-done 72+. Buy it complete and have it thoroughly inspected. You get roughly the same experience as the earlier car for a lot less money.
If you just want a muscle car, find one that appeals to you and shop. Mustangs and Camaros are a lot more plentiful, have a lot more parts available for them, and are cheaper.
