I've never owned a...

A Volvo, a v8 car, or a boring commuter 

a JEEP

a miata

anything European.

I've never owned a Jag You R. 

Somehow I've never owned a Mustang but I guess the Fox platform Lincoln Mk7 came pretty close.

No convertibles.

Never had anything with boost or 4wd. 

Nothing British or Italian

Gosh, I'm boring.

Miata.  Never hope to either 

Any European car without a Volvo badge.

Any two seater sports car.

Any Ford product, ignoring the Volvo connection.  There are some things imprinted during childhood that are really hard to get past.

My last fun car was my only fun car...  so... basically I haven't owned everything.

A British car

An Italian car (though I do have an Italian motorcycle)

A Camaro or Mustang, or a Corvette

An unusual truck (Unimog, one of the -Rovers, etc...)

Tons of other stuff, but those are the things that immediately strike me as gaps that could if not should be filled.

Never had:

- a car with an engine that has an odd number of cylinders (have I4, V4, I6, V6, V8, and V12 covered)

- an American car nor a Swedish one

- a truck, pick up or otherwise (only sports cars and grand touring cars)

- a Porsche 

-  I can almost claim to never owning a Japanese, German, or Italian car but I've had one of each in the last half century (68 Toyota Corolla, 07 BMW Z4MC, 69 Lamborghini Islero S).  And I can almost claim not to have had any automatics - but my ownership of several big Jensens blew that one.

I must be approaching 140+ cars by now but I've never owned:

Anything from GM

Anything with 12cyl

A truck

A brass era car

I do have all engine placements covered, front, mid and rear, and all drive placements, front, rear and awd. 

I've only owned 4 cars (2 being variants of the same model) so it would be a lot easier to list what I HAVE owned! All were 4cyls, Japanese or Korean.

No Miata, no Jeep, nothing with a v12, nothing with odd number cyl count. Let's see. Nothing French. No rotaries. No Saabs (but my ol' Paw had a Monte Carlo and a 99). No costs-house-money wonderfullness, but no eastern blok garbage either. 

American car

Anything with a turbo

A truck of any sort.

I'm fairly astonished by how many of you haven't owned a truck, Jeep, or Miata.  

Oh, and a new one:  I've never owned a car older than I am.

Something really fast. Mid 12's is as fast as I've gone.

Something that really handles well and is completely sorted.

Anything with a turbo

Anything motor swapped 

anything diesel

Anything European

I feel I could check all of those off with an older Audi, but having had friends that owned them, I don't like working on my cars enough to buy one. 

Patrick said:

Miata.  Never hope to either 

get out

A Mustang.

Anything that I didn't improve the handling, braking, or engine performance on.

I've never owned...

-Anything mid-engined or rear-engined

-Anything with pop-up headlights

-A Corvette

-A big luxury barge

-A SUV

-A Miata (I just don't fit, I tried)

-Anything Italian

-A diesel-powered vehicle

-A hybrid or electric car

-Anything with less than 4 cylinders, or more than 8 cylinders

-A vehicle with a CVT

Never owned :

BMW

Anything with a straight 6

Anything with paddle shifters

LS powered

Rotaries

Electric and Hybrids

I'm in the 20-car range, and I've never owned a forced induction vehicle, anything AWD (not counting my wife's Equinox since it's not mine, or my Jeep because it was 4x4), or anything with a V6. I did have a /6 Dart for a short while.

When I first started driving I was the king of $100 cars.  When one broke, sell for $100,buy another $100 car.  Owned so many different cars/trucks /motorcycles, lost count.   Nothing French or Or Soviet Bloc.   No bulldozers, tractors yes.  But I could borrow a track vehicle if need be.

Never owned anything that wasn't built by GM. No turbos/supers.

A GM product. It's a lifestyle choice, really.