I read this years and years ago, long before I started logging reads here, and I have to admit that, having just read it again now, the only thing of it that I remembered was the big bovine creature in the restaurant, arguing to be eaten. And you know, if I was only going to remember one bit, that was the best. Don't get me wrong, I enjoyed the rest of the book, even if I didn't love it, but there's something about that cow. I just find it very very funny, and the last "humane" comment just makes me cackle. The entire restaurant sequence, actually, is a very bleak piece of comedy that's often as cutting as it is entertaining. 

Marvin remains the best character by far, though. He's like a space age robotic Eeyore, and it's no coincidence that Eeyore was my favourite in the Hundred Acre Wood as well. There's something about that deadpan level of mopery...