Proportional
I love the way it sounds. Can't explain it, just do.

Schadenfreude
On a purely superficial level, it sounds kinda cool. Plus, it's a concept that I didn't even realize there was a separate word for until fairly recently.

Vehement
Such a strong word...

Ruminate
I don't use this one enough.

Tirade
I could rant about what a wonderful word this is but, for now, I'll just go with: "Fun. Expressive. Love it!"

Cloy
Just... appropriate sometimes.

Harbinger
Sounds foreboding...

Malediction
Everyone knows "benediction", but how many know his evil twin?

Choler
A throwback to older times, when the four humours still came into the treatment of medicine.

Defenestrate
Learned this word in the third grade and loved it ever since.

Exsanguinate
Right up there with defenestrate.

Hyperbole
A million times more fun to say than "exaggeration"!

Surfeit
"If music be the food of love, play on!"

Replete
Sounds... sophisticated.

Tremulous
I'm pretty sure that I "adopted" this word some weeks back... Haven't been using it near enough if that's the case.

Lachrymose
The wonder of this word brings tears to my eyes!

Countermand
Sounds dignified. Wait... no, I take it back!

Sesquipedalian
Whoever came up with this word had a sense of humour. Bravo!

Malinger
I would write more about this word... but I'm suddenly feeling a little ill.

Fiduciary
Sounds so... foppish.

Antediluvian
I like it. Sounds cool. Even if people do think I'm old-fashioned for using it!

Meticulous
I just like it, okay?

Tutelage
Don't hear this one enough anymore.

Laconic
Because I tend to be far too verbose for my own good.

Mnemonic
Gotta love silent letters!

Chthonic
This is a relatively new word for me...

Knell
"I go, and it is done; the bell invites me."

Supernumerary
Some would argue that this word is superfluous... I would tend to disagree.

Lackadaisical
I'm feeling far too listless to provide any more reason for liking this word than enjoying the way it sounds.

Facetious
I'm sarcastic enough that I should have ample opportunity to use this one, but somehow, I always seem to forget.

Panache
I try to use it with style when I can.

Munificence
"That's my last duchess painted on the wall..."

Tintinnabulation
Has a nice ring to it, doesn't it?

Voiciferous
Just... yes.

Disconcerting
I'd use this one more, except people seem to find it unsettling...

Suffuse
Sounds warm and gentle. Lovely.

Hoary
"An old hare hoar, And an old hare hoar, Is very good meat in lent."

Regale
Shall I regale you with tales Of fishes and whales?

Laudable
High praise to the folks who can pick the Latin root out of this word!

Immolate
I've been burning to use this word for a while now.

Glower
Sometimes it's just the right word.

Comestible
Not to be confused with "combustible".

Pugnacious
Nearly started a fight the last time I used this one!

Salubrious
Makes you feel good just saying it, don't it?

Miasma
Well, if "salubrious" made you feel good...

Inveigle
Never had cause to use this one ('though "invigilate" does come up from time to time). It sounds cool though, eh?

Winsome
Hehe, been hearing this one a lot lately...

Ubiquitous
Think I learned this one from an excerpt from A Christmas Carol.

Confluence
Whee!

Maelstrom
I need to find more excuses to use this one!

Garrulous
Goes with pugnacious...

Renumerate
I'd list all the reasons why I like this word... but it would take too long.

Anathema
Another relatively recent addition to my lexicon.

Plethora
I could give you a myriad reasons why I like this word,
But upon closer consideration
That seems absurd.
In the end, justifications, I need but one;
I like it simply
Because it's fun!

Raiment
Sounds snazzy, doesn't it?

Copecetic
My physics teacher used to use this one all the time. Great word! Thank you Mr. Klatt!

Aplomb
Because it's too hard to say things with a peach!

Caterwaul
Goes with "cacophony"...

Extemporaneous
I can never seem to slip this into casual conversation... always feels contrived.

Sagacious
Guaranteed to make you feel smarter just saying it!

Zyzzyva
Last but not least!