Coin values magazine tends to be overly inflated on their pricing, IMO. I use it as a guideline sometimes when buying. If I can pick up a coin thats not overgraded for 1/2 to 3/4 of the coin values price, then its a pretty good deal.
Likewise, when selling you'll probably get 1/2 the price from a dealer. Anything over that (say if you put it on ebay or something) is the frosting on the cake.
Any price guide is for reference only. Its up to you to decide if its worth it or not. Most dealers go by the coin dealer's newsletter and it tends to be the most accurate, so all the others are pretty much for reference.