Hmm, just going through some games with female characters from the ones I can remember right now :
Tifa with toned down chest would be fairly far up there tbh.
Y'stohla from FFXIV, especially in her black mage getup.
Merill (the elf girl from DA2) was adorable because of the accent of the VA.
New Lara Croft (if we ignore her rude death sounds for a moment
) was a nice mixture of cute and sexy. Old Lara looked awful imho.
All the animu games have probably at least one character that could appeal to anybody, due to the modular nature, as long as they aren't opposed to the art style.
Young Jaina, depending on the artist though.
Some of the probably popular ones I personally can't get behind:
Miranda from ME was too fake for my taste and I don't like thick lips.
All the street fighter characters.
All mario characters.
Short haired Bayonetta.
Kerrigan
Sylvanas (because WoW forum)
As for guys, I guess FF and animu villains mostly take the cake here, at least the ones that are depicted as adults.