Fact (because I say so): TBC > Cata > Legion > ShaLa > MoP > DF > BfA > WoD = WotLK
My pet collection --> http://www.warcraftpets.com/collection/FuxieDK/
For me the coolest is the Cindermane Charger pretty easy to get but not many people go for them. Great size for flying and works good on the ground not as smooth as a tiger but close enough. If my Spectral tiger could fly then that would be my pick.
Flying: Ironbound Protodrake
Ground: Flametalon of Alysrazor
Nostalgia: Rivendare's Deathcarger
Atoms are liars, they make up everything!
I've used Invincible since WotlK and the only other mount I farmed/used is the one from apexis crystals.
People don't forgive, they forget. - Rust Cohle
For flying I use the Cenarion Hippogriff and for ground I either use the water strider if I am in an area with many lakes/rivers or the brewfest ram (not the swift one you can still get, but the regular one that was purchased the first year only)
I think the "coolest" mounts are the ones that are the least common. Black Qiraji Battle Tank and the retired vanilla mounts are that the top of my list for that reason.
I think the store mounts have some of the coolest models, but they're so common that I quickly get sick of seeing them in the game. If the store mount models were used for rare drop mounts or achievement mount collection achievement rewards I think they would be some of my favorites.
I always thought it would have been awesome if the Celestial Steed was a rare drop from Algalon instead of the most common purchasable mount.
I love riding my Amani War Bear on my Night Elf Druid, which took forever since the ONE run I won it on I had to take my shaman.
On my shaman I much prefer riding an Elekk, probably the Blue but the War Elekk isn't a bad choice either.
Sandstone Drake, bc you are the dragon
^ same for Tarecgosas staff
Frostbrood Vanquishers, because Frost Wyrms make me wet
Nostalgia >9000 = Rivendares Deathcharger
I quit during 5.3, but at the time I mostly used:
Flying - Armored Bloodwing or Ulduar Proto Drake. IMO the Bloodwing only makes sense for a warlock or DK. When I see a druid, monk, hunter, etc. on one I think "Really? LOL!"
Ground - Vicious Warsaber. I'd like to get the Vicious War Ram which would be my fave ground but not playing during this shitty xpac.
FOMO: "Fear Of Missing Out", also commonly known as people with a mental issue of managing time and activities, many expecting others to fit into their schedule so they don't miss out on things to come. If FOMO becomes a problem for you, do seek help, it can be a very unhealthy lifestyle..
Big Blizzard Bear.
It has a murloc! Murloc > no murloc
The vicious war ram is epic.
You could have the world in the palm of your hands
You still might drop it
On my priest I use Rivendare's Deathcharger on the ground, and the Ashen or Emerald Phoenix for flying. Sometimes I change it out and use the Silver Covenant Hippogryph.
On my warlock I use the Felsteed, which I like better than the Dreadsteed, and in the air, I generally use the same flying mounts as I use on my priest.
Occasionally I will get out the Netherdrakes, or the Onyxian Drake, just because they are so cool. Also the Twilight Drake, because it is the most amazing color.
Also, I sometimes use my Swift Razzashi Raptor (the green one from old ZG).
I'm partial to the Darkmoon mounts, especially the bear, though the Tallstrider is really cool too. Flying mounts wise, Mimiron's head.
I seem to use my vicious horsey (lush green) and white polar bear most,, vicious warhorse is cool as fuck....
also use my onyxia mount,.