We got Pancakes for Findus out of the library and it's become Hazel's favourite. They're not books I'm familiar with, but apparently the Findus and Pettson books by Sven Nordqvist are pretty popular in the right circles (and translated into 44 languages!)
At first I wasn't entirely sold on it but I really adore it now, particularly for the wonderful illustrations. Nordkvist has a great way of playing with scale, so there are lots of little animals, houses, baths, stairs etc. hidden away in bushes or up trees. You can see some in the picture below (click to enlarge).
The story is also fun, Pettson wants to make birthday pancakes for Findus (the cat) but has run out of flour. When he goes to cycle to the store he discovers his tyre is flat, the repair kit is locked in the tool shed, the key has fallen down the well and so on! Of course they eventually unravel the chain and Findus gets his pancakes.
There's another one in the library where they try and trap a fox, unfortunately it's out right now but I'm putting in a reserve for it when it comes back! Definitely on my wish list at Fishpond for birthdays and Xmas. All the reviews say for 5-7 year olds but Hazel's not quite 4 and is very keen on it so I think they're being a bit conservative.