Top 5 24 Characters?
 

...besides Jack.

1. Renee Walker
2. Chloe O'Brian
3. Tony Almeida
4. Bill Buchanan
5. Martha Logan

And Top 5 villains:

1. Christopher Henderson
2. President Charles Logan
3. Colonel Ike Dubaku
4. Habib Marwan
5. Nina Myers

1. Tony Almeida/David Palmer
2. Tony Almeida/David Palmer
3. Chase Edmunds
4. Michelle Dessler
5. Mike Doyle

Villains

1. Ira Gaines
2. Christopher Henderson
3. Charles Logan
4. Nina Myers
5. Ike Dubaku

President Palmer
Sherry Palmer
Nina Myers
Chloe O'Brian
Tony Almeida