I tend to think of the Iliad and the Odyssey and the Aeneid as a whole -- a boxed set of classics, if you will. But the Aeneid is an outlier, written almost a millenium later, written as a sequel to the epics that had already achieved legendary status. Imagine someone nowadays writing a sequel to Romeo and Juliet in which Count Paris goes on to found another dynastic family to challenge the Montagues and the Capulets -- and it was as good as Shakespeare's original. That's a silly example, of course, but I think it roughly sums up the challenge Virgil faced. Dr. Wikipedia doesn't give me much information about what Virgil's contemporaries thought about the Aeneid, but it seems to have been well-received in its day. Virgil desired it to be burned after his death, but Augustus disregarded this instruction and had it published.
Having a daughter named Julia, I enjoyed Virgil's ad hoc etymology of the Julian dynasty, tracing it back to Aeneas' son Ascanius, or Iulus. Virgil seemed to be linking the name Iulus to Ilion, and therefore directly connecting Rome to Troy. I don't know if that's a scholarly analysis or just me jumping to conclusions, though.
My favorite passage of the Aeneid is in Book III when Dido is wandering the palace, mad with love for Aeneas. She retraces all his steps:
Afterward, when all the guests were gone,I remember reading this on break from college, 18 or 19, laying on the the bed my loved one (now my husband) had slept on while visiting my family. And I felt it, ladies, I felt Dido's pain.
And the dim moon in turn had quenched her light,
And setting stars weighed weariness to sleep,
Alone she mourned in the great empty hall
And pressed her body on the couch he left:
She heard him still, though absent -- heard and saw him.