Vergil is the supreme author in Latin. To read him requires a serious commitment and a lot of determination, but the effort is well worth it. His poetry is sensuously beautiful; every page is filled with vivid, richly figurative language and strikingly poetic expressions that are unrivaled in their originality and power. He is an author of immeasurable sophistication; his narrative genius is immediately apparent even to the most immature reader (like me when I first encountered him in college).
Vergil took to an entirely new level the Latin language and all of the poetic and rhetorical resources that were available to him. He is a kind of encyclopedia of many authors who preceded him, plundering their work and refashioning it for his own ends. Both Greek epic and tragedy, as well as Ennius, Lucretius, and Catullus all reappear now and then in fascinating ways.
It is all here: politics, religion, history, mythology, philosophy, a tragic romance (Dido), brilliant portraits of natural scenery (e.g. in the similes) and more. Vergil is in many ways the standard against which all poets must be measured -- no matter who they are, where they live, or in what period they write. After Homer, he is the single greatest classical author and only students who are willing to learn the essentials of Latin grammar will be able to appreciate his linguistic magic.
This book is a good place to start with Vergil. It contains text, notes, and vocabulary. I have occasionally lent it to students who are beginning to read him for the first time, and they have all reported to me their happiness with the book. It is a superb introductory text for first time readers of the Aeneid. The notes are extremely helpful in unwinding complex sentences and especially in filling out elliptical expressions. Vergil is very fond of dropping "est" and "sunt" from perfect passive indicative forms; likewise, he often leaves out "esse" from the same infinitive form in indirect statement. Little things like this frequently drive new readers crazy, and the authors of this book are sensitive to the problem readers face and quick to offer help.
Perhaps best of all, it provides a fair amount of translation aid without actually doing most of the translation for you.
Labor omnia vincit.