Yellow's quite a strong colour if you're not careful so picking a good one is a challenge, but it's really bright and friendly if you get it right. If you haven't already seen the spare room at Lents Way come over and have a nose, it's a really lovely warm yellow-cream called Sunlight and it gives an idea of the kind of effect you can achieve. Though I think it might be too dark for your living room and it would *not* work with a grey carpet. Rugs and throws, however, can conceal a multitude of sins.

The kitchen is such a lovely room in itself I think it'd really benefit from a facelift. Might be as easy to just change the cupboard doors though - they're melamine or similar IIRC, which would need sanding down to make the paint stick. And even then you'd have to use something with a lasting finish that could be cleaned, and gloss paint is absolutely appalling stuff, it takes pints of white spirit to clean it out of your brush afterwards...