The best selling LEGO set in 2014 is the Desert Skiff. It was created in 2012 and averages around $25 in the store and online.
I think the best selling LEGO ever made is the LEGO city edition.
Lego mindstorms biotic is the best selling set ever made. It has sold over 1 million.
lost temple
star wars
Legos
Yes
Yes, all LEGO sets have a certain lifespan. Eventually, a LEGO set will be phased out so that resources can be allocated for newer LEGO sets.
This really depends on what you want from the set and the Lego person! if you want a cool character you might choose my favorit Lego Indiana jone if you want a non movie character you can always buy a Lego minifig set from Lego!
medieval market village
medieval market village
Lost city of Atlantis
It is truly up to you to decide which set is the best.