It's particulary exciting to find a deep sky object that has only been discovered in the last half century. Maybe that's because you know that not many other people have ever seen it! One of the most significant lists of such objects is George Abell's Catalog of Planetary Nebulae, objects discovered on plates from the Palomar Sky Survey in the mid-1950s.
This compact planetary lies only 40 arcminutes east-southeast of open cluster M34 in western Perseus. From a bright 7th-magnitude star in the southeastern part of the cluster it's an easy star hop along a string of 10th-magnitude stars to a pair of stars of about the same brightness. The planetary is just northwest of these stars. Can you spot it? (Don't miss the tiny galaxy just a few arcminutes further northwest.)
This is one of my favorite Abell planetaries because it is so unexpected! To find it first locate Mu Orionis, a 4th-magnitude bluish star about three degrees northeast of Betelgeuse. Then pop in a high power eyepiece with an OIII filter. All but lost in the glare, and just northwest of the star itself, you may be able to spot a faint circular patch a bit more than half an arcminute wide. That's it!
This large soft planetary lies near NGC 7789, a wonderful open cluster in western Cassiopeia that is on many observers' list of favorites. Look for a pair of 6th-magnitude stars about a degree and a half west-northwest of the cluster. The planetary lies about half a degree south of the reddish easternmost star of the two and forms a right triangle with them. Look for its brighter southeastern edge.
Two other Abell planetaries you won't want to miss are Abell 21 in Gemini and Abell 70 in Aquila. Abell 21 ,also known as the Medusa Nebula, is the crown jewel of the Abell catalog, a large bright horseshoe of light in a 17.5-inch scope with an OIII filter. Abell 70 is fainter and tougher to find, but worth the search, because it combines an overlapping galaxy and nebula. The edge-on galaxy along the planetary's northern edge is much the brighter of the two and actually appears to lie in front of the nebula!