Heh, so, I'm doing the five icons meme again, this time with rodlox
's choices. Well, actually, two of rodlox's choices and three of mine because there were three repeats. :) It happens. Rules are the same, I'll pick five icons for those who reply.
rodlox's two first.
Anita/Eames, from my Inception fic Architecture of Your World and Mind
I don't think it's a secret that I like to cast my fics, and that was definitely true for my Inception fic where I genderbent Arthur (Anita) and Yusuf (Yasirah). I didn't come up with the idea of Summer Glau as girl!Arthur, but I think she's perfect. Mostly I use this icon when posting chapters or replies to comments for "Architecture" or for commenting on other genderbent fics.
Gabriel and Castiel, Supernatural
So, I think this might be a travesty of sorts, but... I ship Dean/Castiel and Sam/Gabriel (not really into Wincest but I see where that crew is coming from sometimes) but... I think I actually ship Gabriel&Castiel platonic brotherly... stuff most of all. We don't get it in the show, which makes me sad, and it also doesn't seem to be a common theme in fic, which makes me more sad. D: Then my response was to write some, because those boys need family who actually gives a damn, really quick. :D Anyway, I use this for commenting on the brotherly!platonic!Gabe&Cas I do find, and on other Supernatural fics where my Dean/Cas and Sam/Gabe icons don't quite seem to fit.
And my three...
Edward Seymour/Anne (Stanhope) Seymour, The Tudors
Oh God, this pairing. Historically a happy couple, on the show almost as dysfunctional as Henry's marriages, which is saying a lot as anyone who knows the "Divorced, beheaded, died. Divorced, beheaded, survived." refrain for Henry's six wives. In the show Anne and Edward hate each other, but the actors' chemistry is... scorching even in mutual hatred. God, they could have been a wonderfully snarky, evil power couple, but no. I use this as my icon on fanfiction.net as well, since most of my involvement there is in the Tudors fandom. I support my ships! (And the right of everyone else to do so for theirs, no ship bashing here.)
Anita Blake and Edward aka Ted Forrester, Anita Blake: Vampire Hunter
OK, I love the Anitaverse, gratuitous, possibly IKEA porn and all. And I love all of Anita's boys, but most of all I love Edward, who is not one of them. He's Anita's soulmate, by a definition that your soulmate, your other half, is too much like you to be your lover. You're parts of a whole, but romance would be like incest. I love the concept, and I love how the Anita&Edward dynamic changes - we meet him in the very first Anita novel and Anita's expecting him to kill her one day; by the last book to date, in which he also figures prominently, he's basically Anita's best friend. These guys and Gabe&Cas (above) are probably my favorite platonic!ships, if that makes any sense, in all my many fandoms. I use this icon basically whenever the hell I want to, no particular rhyme or reason to its use. I just love it.
Katherine of Aragon/Anne Boleyn, The Tudors
Yes, the slash instead of 'and' means this is not a platonic pairing. My default icon is for my fic Handmaid, which was probably the fanfic equivalent of a top-seller (maybe not quite a best-seller, see the brilliant ReganX on ff.net for that...). Handmaid came out of someone on the Tudors forum wanting a Henry/Anne/Katherine fic that was not a triangle but actually involved romance on all sides. While those three never quite worked in my head as a triad, the three couples were definitely fun to write. And Anne/Katherine, more of a romantic friendship due to character and context, is definitely the heart and soul of one of my best fics. It's my default because Handmaid was a turning point in my writing, and I like to remember that.