This is really cool to learn about. I don't think I have synesthesia, though. When it was talking about superior memory I was reminded of people who can memorize tens of thousands of digits of pi, and how they always have synesthesia. They memorize pi like it is a beautiful scene or a song rather than a hard list of numbers.
It's good to know we all have a little bit of this, though. I associate personalities with letters, for example.
A: Outright and punctilious
B: Tolerant and slow
C: Athletic
D: Witty
E: Unique and rather feminine
F: Beautiful and exotic
G: Rich and deep
H: Western and bully-like
I: Cold and sharp
J: Me; colorful; awkward
K: Foreign
L: Flexible
M: Dominant, with a strong presence
N: Very similar to M, but lesser
O: Fat and whiny
P: Provocative
Q: Outsider-like and unwanted
R: Cool and cultured
S: Smart and sassy
T: Well-rounded and common
U: Old
V: European and musical
W: Slimy, huge, and friendly
X: Painful
Y: Asian and traitor-like
Z: Young and annoying; delicious
Yeah that's some pretty random attributes, but it's what comes to my mind!