Fucken
No, not “fucking”. Fucken.
It’s a truly great and versatile word, and no I don’t use it for its shock value. I imagine the sort of people I mix with wouldn’t be shocked for a start. It is simply, in its own right, a fucken great word.
I’ve always loved the word loquacious. And strangely enough, another one of my favourites has already been mentioned:
Cromulent.
Tenebrous.
I’d agree, but there is a sheep variant referred to as callipygian, which kind of ruins it for me.
Besides other words listed here, I would add
sterquilnian (best used to insult publically, with only the priviledged understanding)
autochthonous (just sounds neat)
sequacious
…does not get any google hits nor does Mirriam-Webster list it.
Did you spell it correctly?
Aha… dictionary.com suggests sterquilinous may be what we wanted.
Miss Waggintongue talked so much that she didn’t have time to loquacious going.
Macabre. Just sounds foreign and chilling enough.
Turgid.
I was thinking of this word just today; for some reason I always think of it in connection with the word dryasdust, which is another favorite of mine.
I’ll have to double check a more complete dictionary. I always trust my vocabulary more than any silly dictionary editors. 
I’m thinking I should add tenebrous and cromulent to my list of obscure and good words. I’m also thinking AskNott should be shot.
Cumbersome
Eloquent
Robust
Feeble-minded 
Pretentious
Bombastic
Just to name a few…
I love to use the word muchly.
Also ding is a favorite word of mine. It’s not for spectacular things but if you pull off something a bit special, it gets a ding. 