2,3,6,7,10--they're all ships with...I don't know, challenges, I guess, is the word that comes to mind. The course of true love never did run smooth and all that. Rogue and Gambit can't touch, Remus and Tonks have to deal with his...condition and the prejudice of the wizarding world, I seem to recall there being some issues with Oz being a werewolf, too, but I could be wrong, Anakin and Padme are all kinds of forbidden love, and Logan/Veronica have the hardest time getting it together.

*nods* I do tend to gravitate towards angsty, against-all-odds couples.

I was thinking this as well - the entire "true love never runs smoothly" theme - and would probably even include 8 & 9 in that category. For (8), well, I would think it's obvious that Mai and Zuko haven't had the easiest time of things, what with him having been exiled for a while there, conflicting loyalties, and other potential suitors (depending on one's shipping preferences, heh). For (9), again, there's all sorts of complications. Not least Ichigo! ;)

While I usually have to come down on the Ichigo/Rukia side, I must say Renji/Rukia is good when we pair Ichigo up with someone who is NOT Orihime.

Your comment reminds me that physical distance is a common theme with a lot of my favorite ships. Renji and Rukia were estranged for years decades, Mai and Zuko were separated by his exile, Harry had to leave Ginny for the sake of his duty to bring down Voldemort, Gambit and Rogue may at least get to be in each others' presence, but they are still physically separated by Rogue's inability to touch Gambit without hurting him. I suspect this pattern appeals to me because it gives one or both people the chance to demonstrate outstanding fidelity.

RE: Bleach ships

I must admit I do like IchiHime, too, though not as much as Renji/Rukia. But I'm not as dogmatic about Bleach ships as about HP ships, so rival ships like Ichigo/Rukia and Orihime/Ishida don't really bother me much, except that they usually leave Renji out in the cold. Renji is my favorite Bleach character, so that doesn't really work for me.

Couples 1, 2, and 5 must limit their touch due to physical problems. Another example wold be Bella and Edward in the Twilight series. Just as couples separated by distance find creative ways to develop intimacy and demonstrate affection, these "couples who must not consummate" find other ways to communicate their love for one another. There are many examples of couples who loved from afar in history, for example John and Abigail Adams, when he was in Philadelphia and she was back home on the farm. It is interesting and inspiring to see how they overcome challenges and remain faithful.