Agreeing.
Disagreeing.
Suggesting.
Stressing personal opinion.
That's a great idea.
Why don't we..?
I see your point but...
I think we should...
As for me...
I think yor are right.
How about...
I agree.
As for as I am concerned...
Are you sure?
I wonder if...
We could...
I disagree.
Don't agree.
I hold the opinion that...
Personally I think...
Have you considered?
I am not of the same opinion.
I stick to my opinion.