How do you keep the mobs away from your house at night?

Fencing works very well in this case, as mobs cannot jump over fences, with the exceptions of the Spider.

Remember, you want a lot of lighting around your house. Hostile mobs only spawn in dark environments, so you want plenty of lighting in and out of your house to avoid the chance of a mob spawning or getting close to you.

You can also try building lava traps, like a moat, so mobs that try to get too close end up getting burned as a punishment.

In general, it's all about lighting and keeping the area around your house open and free of darkness.

Lots of torches (and other light sources) will mostly do the job. Mobs won't spawn in light. Surround your house with torches and you'll be fine. Remember that each torch reaches its maximum illumination after 8 blocks (not counting elevation or inclines) when placing torches for maximum mob-repelling.

Since I notice you said you're in Creative, it might be better to use Glowstone Blocks instead of torches, since their field of light is larger, and they are just as good at discouraging Mobs from spawning.

Also remember to put a light source or a non-mob-friendly surface on your roof, because that is a valid mob-spawning location too.

And a wall or a fence will help tremendously in keeping mobs from wandering randomly into your territory, provided they're tall enough that they can't jump over.

Endermen might still teleport in at random though. Besides keeping your vertical indoor space limited to less than 3 blocks, there's not much you can do to stop them.

If you put a fence around your house and put ocelots in it creepers will stay away. If you put tamed dogs loose around your house, you have less chance of getting skeletons close to your house, but you will soon loose your dogs. :)

Run a clocked command block of:

/kill @e[r=range, type =! Player]

Replace range with desired range.

Warning: will kill all non player entities.

Many good answers for Minecraft can be found at the wiki: http://minecraft.gamepedia.com/ for this you may want to look at http://minecraft.gamepedia.com/Spawn

Mobs spawn based off lighting and where the player is. If you stand still mobs will randomly generate in an space where they can spawn within 120ish blocks from the player (big square 240x240 centered on the player) but no closer than 24 blocks of the player.

To prevent this from happening you need to light all of the surfaces within 120 blocks of the edges of your base. Keep in mind, if you do not find all of the caves and underground areas, they may spawn in a caves.