Like everybody else, I have my own personal deep sky favorites. Over the last decade or so, I've collected a couple of hundred objects that I enjoy revisiting from time to time. (Sure, I revisit my favorite Messier objects, too, but I like to encourage people to explore beyond the Messier list.) My list reflects the fact that I observe with a fairly large scope - a 17.5 " Dobsonian made by Bob Coombs of Sky Designs; and from a good dark sky site with a typical visual limiting magnitude around 6.5. Many objects on my list are easy enough in a 6 - 8 " scope, but don't be surprised if some are very challenging, particularly if you don't get far away from the city lights to do your observing.
If you are an astronomy newbie, by all means start out with the Messier List. For more advanced observers, I recommend Orion's Deep Map 600 by Steve Gottlieb (with a Megastar .obs file from Mark Johnston), and the RASC Finest NGC Objects & Deep Sky Challenge Objects by Alan Dyer & Alister Ling. Be sure to check out The Revised AINTNO 100 by Barbara Wilson & Larry Mitchell. If you enjoy our website, you will also enjoy Greg Crinklaw's Skyhound. Check for more observing notes on deep sky objects shown here at Lew Gramer's Internet Amateur Astronomers' Catalog (IAAC) - Jim Shields