Your starting rock is the one item you will see every single life, so it makes sense to get a nice skin for it. You can find a really good top rock skin collection list on CobaltLab that shows off the best designs available. I personally love the ones that have a slight glow because they are so much easier to find if you drop them at night. The blog post has some great high-quality images so you can see exactly what they look like before you buy anything. My favorite is the molten one, but there are some really funny ones like the coconut or the brain too. It is definitely worth spending a couple of dollars to make your fresh spawns a bit more interesting.