Cruise/Holmes vs ... (Evan Agostini/AP)

Then, like the stealthy vampires that they are, along come Robert Pattinson and Kristen Stewart with a cheating scandal and the seeming demise of their relationship, a romance that convinced a generation of (mostly) females that the things we read about in books can totally come true-true-true . . . at least kinda sort of.

The interest in these two stories demonstrates a bit of an age divide when it comes to celeb gossip. The Cruise/Holmes saga is one that, arguably, is of greater interest to the over-35 set, those who have watched Cruise marry and divorce three times during their adult lives and still remember when he was considered the ultimate symbol of male perfection. Some of those same people glance at the Pattinson/Stewart headlines and say, “Who honestly cares about these bland ‘Twilight’ actors?” Meanwhile, an infinite number of young Pattinson/Stewart fans breathlessly sift through every detail about cheating timelines and U-Haul trucks and make YouTube videos that demonstrate their emotional struggle with all this, suggesting that a lot of people care. A LOT.

In other words, it’s hard to know which one to declare the most “important” Hollywood relationship story of the summer. And until we know which one earns that title, how are we supposed to sleep?

Pattinson/Stewart. (Kevin Winter/Getty Images)

Abundant use of name abbreviations

Cruise/Holmes: They were pioneers in the field of Celeb Couple Name Generation. TomKat is the one that, along with Bennifer, started a trend that, frankly, should have ended a long time ago.

Pattinson/Stewart: Not only are they Robsten as a unit, they also have individual nicknames in KStew and RPatz.

Point to: Pattinson/Stewart based solely on volume.

Length of relationship

Cruise/Holmes: They were together for seven years and married for a little more than five.

Pattinson/Stewart: It’s kind of unclear, since they never officially-officially admitted they were dating until she officially-officially acknowledged she had cheated on him. They supposedly started dating after meeting during the filming of “Twilight,” so best estimates are somewhere in the four-year range.

Hollywood significance

Cruise/Holmes: “Rock of Ages” may not have been a huge win for Cruise, but his name is still synonymous with major movie star and has been for nearly 30 years. According to Forbes, he’s also the highest paid actor in Hollywood right now. Holmes has never possessed the same draw but will become infinitely more interesting as her career is tracked post-Cruise.

Pattinson/Stewart: Thanks to their “Twilight” success, each is extraordinarily well compensated. Stewart recently topped yet another Forbes list, of the highest paid Hollywood actresses, while Pattinson was just a few notches behind Cruise on the male version of the same rundown. However, it remains to be seen whether both can sustain that juice once the “Twilight” saga ends.

Point to: Cruise/Holmes, because of Cruise’s seniority and the fact that his image will probably take more knocks, and Holmes’s will get more of a boost, than Stewart’s or Pattinson’s will if they split.

View Photo Gallery: The Hollywood stars called it quits after more than five years of marriage.

Juiciness of break-up circumstances:

Cruise/Holmes: Holmes initiates a divorce, blindsides one of the most famous men in the world and settles the whole thing lickety-split while starting over in Manhattan like a single-mom version of “That Girl,” leaving Cruise’s attorney to threaten tabloid lawsuits. It’s a great story, no question. But it’s more mysterious (as you’ll see below) than juicy. Although it’s the mystery, really, that makes it juicy.

Pattinson/Stewart: Stewart cheats on the teen heartthrob of the moment with an older married man who was also her boss, then apologizes publicly to Pattinson while he reportedly leaves their home heartbroken and angry. That’s a classic juicy — with added pulp — Hollywood gossip story.

Point to: I don’t know. This might be a tie.

Shroud of relationship mystery

Let’s just stop right here and say that point goes to Cruise/Holmes, who are remaining mum about the whole thing. When second cellphones get involved — a la “The Wire” and/or “Breaking Bad,” take your pick — you are the gold-medal winner in this category.

View Photo Gallery: Kristen Stewart issued an apology to ‘Twilight’ co-star Robert Pattinson following rumors that she cheated on him with “Snow White and the Huntsman” director Rupert Sanders.

Conspiracy theories

Cruise/Holmes: Oh, as Celebritology readers well know, they abound and involve everything from Scientology to the paternity of Suri Cruise.

Pattinson/Stewart: The most notable one involves the notion that the alter egos of Bella and Edward have only been “dating” for publicity purposes.

Point to: Cruise/Holmes. Few celebrities spark a desire to spin wild ideas about “what’s really going on” the way Cruise does.

Length of projected time that break-up will generate headlines

Cruise/Holmes: Several months and probably longer. Every move Holmes makes — including showing her clothing line at New York Fashion Week and starring in a Broadway play — will be scrutinized. Same goes for Cruise, who has “Jack Reacher” to promote this fall and winter. The first interviews both decide to do will be the proverbial “big deal.”

Pattinson/Stewart: Same deal — several months, at least, certainly throughout the publicity tour leading up to the release of “Twilight: Breaking Dawn Part 2” in November and probably long beyond that.

Point to: Once again, a draw.

And the more important Hollywood relationship story is . . . the Tom Cruise/Katie Holmes divorce, at least for now. They were married, we’ve been dissecting their relationship for years and the private details around their divorce makes it a subject of infinite additional dissection. The Stewart and Pattinson story is still young, though, and has the potential to take some interesting turns. Edward Cullen, if it turns out you had a secret cellphone, this whole matter may require re-evaluation.