|No I don't know who snapped this little picture.|
As you can see from this picture Cobblestone by itself looks like Crap. Then again building with a 'fill in the holes with x (where x is dirt, sand, or whatever) approach will look kinda crummy.
On the other hand if you mix materials with some sort of pattern in mind (even if said pattern will only get organized later on) you can end up with some bits of interesting.
|See how mixing cobble with smooth makes things a little less suck?|
I offer some of my own work (that comes from a few months ago) as counter-examples of how cobble can look Non-Suck. Yes Yes painterly helps since it gives a different texture to things, but it's still 16x16 pixel tiles, so you're not gonna get crysis level graphics. Put a little work into it and you get some pretty spiffy stuffs.
|Done at the end of my first day|