I have to totally agree with you: I loved Kraken.
One of his first books, King Rat, a standalone with elements of horror and elements of epic mythology, is rather remarkable too.
And, though Un-Lun-Dun is ostensibly a novel for young adults, it has layers of complexity and philosophy which are captivating and enthralling.
I'm embarrassed to admit that I started Perdido Street Station but haven't (yet) finished it. (I'm going to have to restart it from scratch, obviously.)
But I did finish The City and the City - and although it's a moderately dense read, it's worth it. The other weird thing worth mentioning is-- some enterprising English television producers actually adapted it into a semi-sci-fi-semi-film-noir series a few years ago. I started watching it and was very, very glad that I had read the entire novel first, since for me, the adaptation didn't come close to some of the weirder-but-cooler parts of the premise and the novel.