I love london, I love food and exploring. I can't stand generic chain coffee houses and cafes. This Cool Guide to London is a few years old now but is still an excellent reference if you're looking for something a little different to do day or night.
The really excellent thing about this guide is that it is also translated into four different languages, so it really is an excellent tool for tourists visiting London for the first time. I can totally verify that the places it recommends are, as it suggests very 'cool'!