Caulk around bottom of toilet?
This is an argument that seems to never end. I work for several hotels and in every single room the toilet is caulked. It just plain looks nicer and it helps to stabilize the toilet. Some say that it will hide a leak but that makes limited sense. If a toilet leaks at the base, it's usually related to the flange leaking. Now, if the toilet gets cracked for some reason you might get a leak there but that's rare. Also, what if someone or an animal urinates and it gets underneath the base of the toilet? How would you clean that? Consider just water sitting under there and stagnating. I'm a big fan of caulking around a toilet. Although, you have to do it right. Use tape if you are inexperienced and don't buy anything cheap. 

If you do choose to caulk, use a 100% silicone mold-resistant caulk like GE.