Neutral:
* Alright
* Sure
* Got it
* Understood
* Fine
* Right
* Yes
* No problem
* I see
* I hear you
Positive:
* Great
* Wonderful
* Excellent
* Perfect
* Sounds good
* I'm happy with that
* I'm on board
* That's great news
* I like that
Enthusiastic:
* Awesome
* Fantastic
* Amazing
* Terrific
* Sweet
* Cool
* That's fantastic
* I'm excited about that
Hesitant/Cautious:
* I'm not sure
* I'll think about it
* I need more information
* Maybe
* I'm not sure that's the best idea
Formal:
* Agreed
* Very well
* I understand
* That will be fine
* I'll accept that
Informal:
* Cool beans
* Sweet
* Rad
* No sweat
* You bet
* All right, cool
Specific to Situation:
* For a request: "I'll do it."
* For an agreement: "I agree."
* For a confirmation: "That's correct."
* For an understanding: "I understand what you mean."
Remember to choose the word or phrase that best reflects your feeling and the context of the conversation.