I quite like Miranda Hart, unfortunately she's funnier on chat shows than on her own shows. If I told you what I think of Gervais I'd have to ban myself...
I echo Paul in, each to their own. All personal taste. I think all you listed are in the "ok" bracket. Although I think Ricky was best when he first came to my attention, a sort of regular guest slot on a late night show, the name of which escapes me for the moment.
I enjoy watching Ricky Gervais and Catherine Tate. Miranda and Keith are not to my taste. I get personally annoyed with myself if I let out a laugh whilst watching either of them
I liked the Office and some of the Extras episodes were rather good, but as a person he is horrible. Whenever I see him being interviewed he is always smirking...dreadful oik.
I like all of them. Keef Lemon is an acquired taste and I find him funny. I think Leigh Francis is a brilliant character comedian. I don't think I've ever seen him be himself anywhere.
I totally agree with the OP, all unfunny... with one exception which is the 'Ricky Gervais show' (The animation pod cast one) which in my opinion should have been called 'The Karl Pilkington show'. It wouldn't have been noticed if it were but he is so funny.
I think RG has talent, great writing talent. He just doesn't make me laugh. As for that Hart person and whatever Keith Lemon is... no thank you. CT, I've never seen. She seems to be quite "gobby" and unfunny. In fact, apart from Harry Hill, no "comedian" makes me laugh. All, sooo unfunny.