To make it easier for those of you who don't want to play any custom level to find a good one, I will make a list of levels that are recommendable. Please feel free to add to the list, if you have any good levels to recommend.
Aegean Legends (Trix)
Cave Of Pandora (Hokolo)
Deep in the jungle (Hokolo)
Flying Temple (Codo)
Fragments of the Core (Horus)
Hanami in Kyoto (Miss Kroft)
Hidden Garden (Inchdix)
Last Crusade (Piega)
Legacy of the Gods (JediMaster)
Lost City of Pompeji (Michael Allen)
Lost Valley (Jeyem)
Mystery of Eden (Sweet)
Pirates of the Caribbean (Michael Allen)
Quick and the Dead (Hendrik)
Sanctuary of Water Ice and Fire (Piega)
Search for Imhotep (Palo)
Walhalla (Miss Kroft)
Ynys Witrin (Miss Kroft)