I can only talk about those I watched.
MEN TOP 10
Laver
Mc Enroe
Nastase
Connors
Panatta
Rosewall
Becker/Santana/Roche/Edberg/Orantes
Newcombe/Sampras/Ashe/Gerulaitis/Kriek
Agassi/Pecci/Lutz/Mecir on a great day
There are 10-15 more players really exciting like Ramirez, ,Stich,Cash,Rafter,Mayer,Gomez and some days Leconte who could make it to my top 10
Borg had also something exciting about him.
WOMEN
Mandlikova/Goolagong
Bueno
Hingis
Navratilova/Court
A Jaeger
Seles/Wade/Venus/Jordan
Bunge/Fromholtz/Ruzici/Casals
Graf,Sabatini,Martinez,Hanika,Kournikova and some times Kuznetsova and Sharapova were also great watching, too
My top 10 of those non watched, at least what I figure out
1/Hoad
2/Gonzales
3/Cochet
4/Budge
5/Drobny
6/Crawford/Patty
7/Vines/Borotra
8/Sedgman
9/Pietrangeli
10/Doherty
1/Lenglen
2/Connolly
3/Marble
4/Gibson
5/Dupont/Lily Alvarez
from 5-10 I´d have big trouble ranking.I guess all the past time champions had exciting aspects in their games