Ilia: proving since 1979 that you don't need Rapunzel-like tresses to be totally gorgeous.
Ilia: also proving since 1979 that you can be evaporated, put back together as a sentient android, and still find everlasting love.
What do we talk about when we talk about Ilia? Well, we'll be talking about the two versions of Ilia.
The first is the real Ilia: the newly hired helms officer of the Enterprise who was once romantically involved with Willard Decker. We don't get to know that girl too much—besides the fact that she must have inspired at least a couple of women to rock the Daddy Warbucks hairstyle.
The Robot Blues
Instead, we spend the bulk of our time with a character we'd like to dub "Robo-Ilia"—an unholy hybrid between a Starfleet officer and living machine. According to her, she was "programmed by V'Ger to observe and record the normal functioning of the carbon-based units infesting U.S.S. Enterprise."
In fact, she's the one who reveals V'Ger's name.
The crew attempts to reawaken the real Ilia within this android by showing her things from her past life, like the games and clothes she used to enjoy. This will usually work for a second or two, but she inevitably slips right back into being a mechanical zombie. Decker in particular is hurt by this. He clearly still has feelings for his ex-bae.
Peeking to the Surface
Interestingly, however, Robo-Ilia seems to have some residual feelings too. We can see this most notably in the fact that she refers to Decker by his actual name from the get-go, rather than stylizing it as "Decker-Unit" like she does with everyone else on the crew.
We'd argue that this connection is the real reason why V'Ger chooses to merge with Decker. After all, it's been struggling to figure out these weird human emotions, and now it's been struck by the most powerful one of all—love. D'aww.
In this way, we can take small comfort knowing that Ilia and Decker's connection still lives on strong, even if their physical bodies might not.