No offense intended to any reader named Gertrude or Hortense, but frankly, neither of those names makes me suspect a supermodel is attached.
What names just say, “Wow! She (or he) has…um… a great personality.”
Bertha of course.
For guys, I suppose Sheldon and Lester are not names you would normally associate with a hot young stud.
(But, hey, names aren’t destiny, as I’m always reminded by the Winner/Loser Lane story)
Hulga (since Bertha was taken)
Lenny
The last book in the Anne of Green Gables series is about Anne’s youngest daughter, whose full name is Bertha Marilla. She hates her nickname “Rilla” and wishes she was called by her dignified first name.
The story is set against the backdrop of World War I. The associations with that name have really changed!
The TV Show the Big Bang has two nerds named Sheldon & Leonard. I wonder how they chose those names 
Oddly enough, any Norse names (Olga, Helga, and so on) fit the bill here, even if Norse women tend to be known for their stunning beauty. Eugenia also springs to mind. For guys, Eugene, Willard and Troy.
**Griselda
Emily
Malvina
Magda
Dagmar
Sophie
**
Of course I’m reminded of a line from When Harry Met Sally
Harry: Have great sex with Sheldon? No, you didn’t. A Sheldon can do your income taxes. If you need a root canal, Sheldon’s your man, but humpin’ and pumpin’ is not Sheldon’s strong suit. It’s the name. ‘Do it to me, Sheldon.’ ‘You’re an animal, Sheldon.’ ‘Ride me, big Sheldon.’ It doesn’t work.
Um, Emily? 
One of these things is not like the other…
I don’t think Sophie belongs on the list either.
Ethel does though.
I always get a Little House on the Prairie vibe from that one. Emilys should have straight long hair, braided or kept in a bun, and wear long aprons.
Yes, Emily. Doesn’t work for me at all. Think of al the hot Emilys out there:
Emily Post
Emily Dickinson
Emily Litella
Sorry, folks. Maybe you like Emily. To me even the sound of the name is unsexy.
Glad you liked the others, though.
Troy? Really?
Gotta go with “Beulah” for the ladies, and “Bubba” for guys, but that might be my northern bias showing through
Most of the names here are names that, if they were ever popular in the US, were popular at least seventy years ago. That means that if you’ve ever known somebody with those names, they were probably elderly, and not super-hot. These things tend to cycle - in a generation, nobody young will have ever known anyone with those names, and they’ll sound fresh and new again.
I used to think that, until I met a really hot Ethel.
I also love Emily.
The yuck names for me are Bertha, Griselda, Anne, and Lydie.
Eunice
Ethyl
Edith
Ester
Gladys
Hazel
Phyllis
Hiram
Grover
Phinneas
Myrtle and Mabel and Ethel for me.
And according to this site, Eulalie hasn’t been popular AT ALL since the last century.
Vernon and Eugene also. About 16 years ago I met a young boy named Vernon…his parents were older, in their 50s, and I felt sorry he got saddled with that name.
My middle name is on your list. It was both my grandmother’s first name so it was almost unavoidable.
Shirley and Ida. My grandmother’s names.
My dad is a Howard and that also sounds ugly. His brother is a Frederick but that just sounds dashing.
I’ll add a variation of my own name to the list–Marjoram. As much as I dislike my actual name at times, it doesn’t scream ‘old lady who smells of medicine’ nearly as loudly.