I thought I might impart a few thoughts on naming your puppy.
1. Keep it short. Two syllables is should be the limit. Trust me, if it's longer than that you won't be using it. As a kid, I named my first dog Persephone (of Greek myth fame). Beautiful, meaningful name. But what did we call her? Not by 4 syllables, you can be sure. No, we called her Seph.
2. Avoid names that sound anything like obedience commands. Stacey is too close to "Stay" and Neil is too close to "Heel."
3. Be positive. I knew of a dog named, wait for it, "Idiot." And another named "Dammit". Pretty funny, eh? Poor dogs started everyday being called "Idiot" and Come here, "Dammit". If you watch obedience and agility competitions you'll see alot of dogs with positive names like "Zipper", "Awesome" and "Turbine", names that conjure up images of speed and alertness. These type of names start each interaction with your dog with a positive frame of mind. Yes, the dogs don't understand what the words mean but you can bet they pick up on the vibes they create.
With a Bullmastiff you might go for names that bring up images of steadiness and strength like "Granite" or "Oak." "Panzer", "Sherman" and " 'Dozer" are popular too.
Names like "Satan", "Devil" or "Mad Max" give the public the wrong impression of your dog. It's cute when a toy poodle is named "Killer". It's a disaster waiting to happen when it's a Bullmastiff. If you go into court on a dog bite charge, regardless of the facts, you're going to lose if your dog is named "Satan."
4. Make sure you give your dog a name you won't be embarassed to say loudly in front of a group of important people. You don't want to be in front of you future in-laws calling "Here Mister Peekipoop." Make sure it's something with which your significant other feels comfortable also.
5. Do not give your puppy a name that sounds anything like names of your family members or your other pets. I give all of my dogs names that start with completely different sounds from each other. It helps keep them from being confused and it helps me, too.