Right now, at this point in time, I don't believe there to be any heel as meaningful as Orton. That being said, this implosion of Legacy angle is either a pretty weak face turn or a badly booked face turn for Rhodes and DiBiase. He's lost the steam he had coming out of the Koft angle since going against Sheamus at the Rumble.
The guys I see standing in line right behind Orton as top heels are:
CM Punk
I hadn't watched wrestling from 2001 to early 2009, and I hated Punk the first time I saw him, as a face. Boring as ALL hell. But his heel gimmick is 100% gold. I've since looked up his past work. I don't think many would work in his role, as he lives the gimmick.
Post heel turn, I have been amazed at his ability to work up good heel heat at almost any time, in or out of the ring. His taunts are some of the best (I loved him pointing at Cena, mouthing "go to sleep", and placing his hands by his head and lying his head on them. GOLDEN!). Also, he got screwed a bit by the back office while overseas (resulting in his HIAC match being bumped down the card and rewritten into a squash), and he took it like a man, never gripping online, not threatening to jump to TNA, etc.
Lastly, I love the SES as it reminds me, and I'm sure many others, of Raven's Flock. Again, if anyone can do that gimmick perfectly, it's CM Punk. The beard is a nice touch.
The Miz
Again, another one I hated when I first saw him. I was solidly on the Morrison bandwagon. Miz was coming into his own post draft night, picking fights with Cena and getting embarrassed. Almost banned from the Summerfest, I hear.
Bragging Rights changed that. The Miz looked stronger in the promos with JM leading up to it. The Miz looked stronger coming out of their match. The Miz has stepped up, from annoying big mouth to annoying big mouthed up and comer. His push keeps growing stronger, now holding the Unified tag and US titles (coming out with 3 belts looks bad ass, no matter who it's on). Somewhere along this line I started seeing him as a threat to others, and ready to move out of the mid card.
His work on NXT with Daniel Bryanson has sold me on his potential as a top heel. He just has it; the intangible characteristic of being able to stand out amongst many of the others before and after his rise. While JM has floundered on Smackdown with little direction, Miz has been given the ball, to a degree, and damn has he run with it.