Y'know, I'm mostly neutral on the old Hobbit cartoon, but one thing I did rather love in it was the depiction of Smaug.
In fact, in terms of presence and personality, I can't think of more than, oh, one other dragon with the same degree of presence as Smaug has here*, with the strobing spotlight eyes and the booming voice. Having watched a random clip of the Hobbit trilogy Smaug, I had to respond "what's up with this weird flat little hissy guy?"
(Also still holding out for David Kaye doing a dragon character voice, seeing as how his BW Megatron voice was basically an ideal dragon voice already.)
*Draco from Dragonheart; much as I love Granamyr from the He-Man series, he's got the presence of a huge old man, not a furious dragon. Which kinda fits; he's a lot more scholarly than the average dragon, and his main claim to extreme dragonlike power comes from the fact that he's the most powerful wizard on a planet crammed with extremely powerful wizards**.
On the subject of voices of dragons, on the extremely unlikely off-chance that I was ever casting current voices for a He-Man cartoon, Hector Elizondo, who voiced Wan Shi Tong in The Last Airbender and Viragor in the Thundercats remake would be my ideal Granamyr voice.
**A relatively mid-range pair of Eternian magic users combined their magic to create a spell that knocked one of Eternia's moons from its orbit. Granamyr was unambiguously much stronger than another individual who was ambiguously stronger than an individual who was stronger than either of them. Which is to say Granamyr's a really powerful wizard.