Expressions of suggestion: 
Making a suggestion:
Why don't we....? We could... How about+gerund (v+ing)...? What about+gerund (v+ing)...? Why not+infinitive...? Let's (not)+infinitive What would you say to...? Don't you think it is a good idea to...? Does it matter if we...? Shall we...? Accepting: Why not? That's a good/great idea! Yes, let's. Yes, I'd like/love to. That sounds like a good idea. That sounds like a good idea. Yes, I feel like + gerund ... Declining/Refusing/Rejecting/Turning down: No, let's not. No, I'd rather not. I dislike+ gerund... What an awful/bad idea! Yes, but... Dialogue:
Two friends talking about where to go this evening:
Alice: You know Alan, why don't we go to the cinema to watch Titanic? Alan: No, let's not. We've seen the film many times before. What about going to the library? We have to finish our school project! Alice: That sounds like a good idea. But when we finish let's go to the cafè. Alan: Yes, I'd love to.