Amnesiac Lover: the point of one storyline. A knock to the head makes Vinci forget everything that has happened since he moved from Greece to the United States, like learning the English language or being in love with Arty. What makes it worse for Arty is that pre-immigration Vinci was apparently kinda homophobic.
Camp Gay: Arty could be the poster child for this, in the Furry Comic world. Though Vinci's outrageous girliness definitely counts too.
Chocolate Baby: A variation; Vinci's parents are legally purebred chihuahuas, both of whom had "recessive raccoon genes" from way back, producing a pureblooded raccoon son who also could have legally registered as a purebred chihuahua.
Darker and Edgier: Ms. DeWalt regularly produces material for Jack, often with much a more violent and depressing style than the normal comic material, and Word of God says this is canon.
For those not interested in wading through the extensive archives and gory/angst-riddled side stories: Vinci and Arty adopt a daughter, Greer, as noted below. Eventually, Vinci gets cancer (Jack's "It's Like Cancer") and fights it off; they grow happily older together until Arty dies saving a stranger from a fire. Vinci, unable to take the loss, commits suicide, which in the Jack-verse damns you to Hell while Arty is an angel in Heaven's legion, forcing them to be even more separated than initially. At the point the side stories are at, Vinci's bakery has been destroyed and he's been half-eaten by the cannibalistic Vorsches while trying to defend one of his only friends. Arty can't redeem him because Vinci simply refuses to accept that he's earned it.
Note that even these Darker and Edgier bits are still extremely cutesy, and full of the kind of melodramatic Narm that would not be out of place in a Gundam Wingyaoi fic, so "dark and edgy" is kind of relative.
Dude Looks Like a Lady: Vinci. And Vinci doesn't even do this on purpose — most strangers will still confuse him for a girl. At one point Vinci even shaved his head, and someone still thought he was Sinead O'Cooner.
Gayngst: Vinci exhibits this trope often, especially when the couple's more conservative neighbours show off their discontent for the homosexual duo.
Arty goes into this one as well whenever his family comes up: he blames his father's suicide on the fact that he'd come out to him earlier that day.
Guest Strip: Frequently has other artists post guest strips. Which can cause some confusion as some guest pages are more canon than others.
Lethal Chef: Vinci, at one point, made cookies that got mistaken for fish, when the character had a crossover with another furrywebcomic, A Doemain of Our Own (ended). In general, the results of Vinci's cooking are usually depicted with a cloud bearing a skull and crossbones (like the poison symbol) on the "scent cloud" for a reason
As of recent updates (2010-09-26) it's looking like Vinci's Lethal Chef abilities may be caused by difficulties reading English recipes; he's prepared food from an all-Greek recipe book and had it turn out just fine. This would explain why he believes his food should turn out edible and tasty, though - after all, before he came to America, it did; he's just been overestimating his ability to coherently read English.
Mr. Seahorse: A literal example with the anthro seahorse, Arkie Illions; "The only guy I know who's so braindead, he was the one who came back pregnant after a wild party."