first house, all the way back in alpha 1.1.4? that was awhile back. It was basically a square shack with a stair shaft going to bedrock level. My main problems occurred when I started experimenting with lava, burned doors, made entry impossible, good times. I later added a skyway to my nearest cave entrance (it was on a hill), and a glass underwater tunnel to the other side of the ocean that I was at (so many stacks of glass, omg). I finally retired the world after making a boat elevator (I miss those, so easy to go down after they were built) and experimenting with rails.
Don't remember. I think it was a hole in the side of a cliff. Problem was I wandered outside shortly after dark on the first night and died. Never did find that place again.
My second dwelling was in the side of a hill, that I began digging out to build a mineshaft The place had no iron to speek of, and all the blocks dug out went into my 1st permenant house (Castle Doom!). The orgional Castle of Doom. Now she has class. Secret doors, pit traps, throne room, tapestries, towers, and a secret labotary. Ahhh good times.
Had all the amenities of home too. Even has a Pool of Doom, Green House of Doom, Sand Pit of Doom, Labatory of Doom, and of coarse you guessed it. The Temple of Doom.
For a long time my green house was 4 dirt walls connected by an underground single wide tunnel. Everytime I went out onto the surface I exploded or was killed by something. I didn't have armor back then, it was awsome times. Everything looked like crap till I figured out how to protect myself from unwanted "Friends".
Depends on what you consider a "house". The first time I went out of my way to specifically build a house, it actually came out quite nice. Roughly 9x9x4 for the first floor. A single vertical beam on the center block with a ladder that went up to a second floor, which was slightly larger but with a shorter roof, and lined with fences instead of walls. It was a perfect place to shoot mobs at with my Bow, without any mobs - aside from spiders (though I eventually changed the design so even they can't get in) - able to retalliate. The same pillar went down to the basement, which eventually turned into my mine, storage chambers, and underground farm.
I was very happy with that house, but I've got some far more interesting (though less functional) setups I build now. Even today I still build my first house when I need more of a "small fortress" instead of a comfortable place to live.
Of course, my first "camp" was a small hole carved in the mountain. It was never considered a house.