Tell me the build you are most proud of on minecraft! mine is when i build a fighting arena on my friend's server.

I'm proud of my first house that wasn't a hole in a mountain (everyone starts with those anyway ). It might be silly to be proud of that, but I was proud to have gotten far enough to do that.

I was later proud of completely surrounding a large island with a wide walkway of stone bricks, including a couple wooden bridges.

On the Xbox me and my friends created an underground civilization. It's made by about 10 of us and some other come and goers. Each of us have our own rooms, so it's huge.
We also got 2 or 3 quarrys that lead down to slime farms and a castle surrounding the nentrance underground.

Mine was just a silly little boat... Which got over shadowed the next week when my friend built an entire battleship right next to it... <:T

It would either be the ridiculous obstacle course I built on the VR server before it went into a temp. world or the floating house that's at the end of the obstacle course. There's just something about floating buildings that I enjoy in MC. That or underwater buildings.

Mine was a Lava Fountain, caved by glass, and a Water Fountain over it. Anyone know a way that I can upload pictures from Xbox360 MC?

So far, my best build is an aesthetically pleasing and compact adjustable enchanting library with three (four if you're technical) settings. One for low-level enchantments, one for mid-level enchantments, and one for high-level enchantments (calibrated for 1.3). I'll probably have to rip it up and build it again due to the piston changes in the near update, but building's the fun part, anyway.

I built something I named "Saturn Tower" a few months ago.
A tall tower with rings floating around it. Also three large glass spheres above it, covered in water. A waterfall also falling down through the central part of the tower. Also balconies. Or whatever those should be called...

I recently built a massive spleef arena

The Citadel is my greatest build.
At the spawn point there is a diamond monorail that takes you to main complex. When it stops you get of and push it back (it's mostly power rails). The entrance to it is also made of diamond blocks. You climb down the ladder until you get to the main room (not made of diamonds) there are four different rooms you can go to, as well as a library that you climb an adjacent ladder to. The library is, you guessed it. Made of diamonds.

Mine is my flying ship and later a castle that I built out on the server.

As I learn more and more about this game, my builds get better and better. My best one so far is a house where the entrance is completely hidden from view by Jeb's Door [if you don't know what Jeb's Door is, it's basically a piston door that' completely blends in with the wall it's in when closed]. Inside the house is almost everything I would need to get whatever resource I would need in a fairly compact space. So far it has an enchanting room, brewing room, treasure room, and various farms downstairs [so far wheat, pumpkin, melon, netherwart, sugar cane and cow]. Planning to add a portal room, crafting room, deluxe bedroom, mob grinders and other farms [cactus, mushroom, tree, chicken, sheep, pig and a pond for fish]. A path from the farming floor leads to my strip mine, where I mainly mine obsidian to line the walls, floors and ceilings with obsidian [To keep creeper damage to a minimum].

I should take pics sometime to show it off...once it's finished.

If I actually feel like completing it, my best build might just be my double-zombie spawner fall trap-to-1HP in the VR server. How is it that a fall trap and drain is simple, but the moment you add another it becomes rather complex of a build?