I really think the Malekith/Kurse arc is an awesome movie waiting to happen, too.
Picture this:
Loki strikes up a partnership with Malekith to take over the 9 realms. They lure Thor into a trap where he engages in battle with Algrim, Malekith's second in command. Thor and Algrim are sent hurdling into lava, and while Thor narrowly escapes Algrim is horrifically mutilated. Loki (replacing Beyonder) saves Algrim and transforms him into Kurse, significantly boosting all of his powers. Kurse is tricked into thinking the whole thing was Thor's fault and freaks out, setting about destroying Thor's life. Meanwhile Loki, Malekith and the Dark Elves set about overrunning Asgard and causing chaos.
Battles and tragedy ensue in Thor's life before Kurse realizes the whole thing was Malekith's fault. Kurse and Thor together journey to Asgard to stop Malekith and Loki. Kurse dies heroically in the process, but not before murdering the **** out of Malekith.
Of course, that whole story could also basically occur with Enchantress/Executioner taking the places of Malekith/Kurse (although Skurge wouldnt kill Amora), but Kurse is one of my favorite Thor villains. Especially when he's freaking out at Thor.