This is still easily the most saught after set of cards. 4th Edition was a completely new set of 1-500 cards, with a 20 card chase set (1 chase per deck). The deck still was bought with a double-deck format, but the other deck box held a Draconomicon Booster pack.
This set brought back all the key cards from various past sets, and really brought great strength to the game. Its a pity they ran out so quickly. The set strengthened all worlds and themes, and made them viable for high level play. This is also the first time we see unarmed combat cards for dragons, undead, elf(drow), and Unarmed Combats cards for any champion to use. It also gave us the new designation of Adventurer and Dwarf(mul).