The Aeneid is a Masterpiece
Vergil is an anglicized version of the poet Vergilius' name, but most English speakers seem to know him as Virgil. Here I'll use what seems to me the more authentic spelling. Vergil's Aeneid was considered the masterpiece of Latin literature by Romans of his day. Why not spend your time reading what the people who had greater access to other Latin works now lost thought was the best sample of their work?
Even after his death, Roman writers still counted Vergil the master.
"The medieval tradition of allegorical interpretation of myth also owes much to Boethius's 'Consolation of Philosophy,' which, along with Virgil's 'Aeneid,' was a central curricular text throughout the Middle Ages."
Medieval Theory and Criticism
Later literature owes much to Vergil. Dante's Divine Comedy makes little sense without understanding the Aeneid.
Small Latin-English dictionaries, like the Collins Gem, use Vergil-based vocabulary. This means you probably won't have to lug around a tome if you take your Aeneid to work with you. Some Latin dictionaries cover later Latin, others the Classical period. Special vocabulary such as you might find in the early poets, like Plautus, or the more colorful writers like the author of the Satyricon don't appear in your smallest portable lexicon.
Each summer I work on the Aeneid and for a couple of years have not had to take a book along with me each day, as long as I know I'll have Internet access. All I need do is Google "Aeneid" to wind up with annotated public domain books used in 19th and early 20th century classrooms and other programs that make it pretty easy to read notes or look up words almost instantly. You can, for instance, use the Perseus project Aeneid, which lists a small number of lines at a time, two translations, two sets of notes, and an incredibly simple interface to the standard lexicons.
Scanning Tip / Trick
Dactylic hexameters, the meter used throughout the Aeneid, make it easy to spot 3d plurals and ablative singulars of the first declension even in texts without macrons (the long marks over vowels).
Trojan War Mysteries
At the end of the Iliad, much of the story of the Trojan War is yet to come. The Aeneid answers some questions you may have. In addition, the Aeneid tells the Trojan Horse story from the Trojan perspective.
Compact History of Rome
When you read the Aeneid you learn the legendary history of Rome. This is the basis on which to build your understanding of Roman history.
Carthage vs. Rome
The Aeneid provides a legendary explanation for the hostility between Carthage and Rome.
The Aeneid is action-packed and fast moving. You want violence? It's there. You want romance? It's there, too. Treachery, intrigue, revenge....
Vergil includes the great themes of epic literature: exile of the hero, relationships between humans and gods, love, death, loss of innocence, and sacrifice.
"In the 'Exposition of the Content of Virgil' Fulgentius [fl. 500 A.D.] reads the Aeneid as a human pilgrimage from birth to adulthood, from ignorance and error to wisdom and virtue, seeing the narrative action of each book of the 'Aeneid' as an allegory for each stage of this process: the shipwreck stands for birth, Dido's funeral pyre stands for the self-consuming flames of adolescent passion, the descent to the underworld in book 6 stands for the penetration of the mysteries of knowledge through philosophy and experience, and so on throughout Virgil's text."Epic Poetry
Medieval Theory and Criticism
Vergil's vocabulary reveals details of daily life in ancient Rome, Roman weaponry, and ancient farming.
If you need some more help with the Aeneid, see Rose Williams' The Labors of Aeneas.