My first large project is complete! I'm in the process of putting the video together as I type this (final check of the recording to make sure it's not completely horrible). I spent many hours over the last few days digging out tens of thousands of blocks to make a slime farm. The process went through scores of pickaxes and shovels and was a lot of work. I ended up gathering multiple stacks of iron, gold, and coal, plus a ton of redstone, and about 20 diamonds. Overall, I ended up with a lot more materials than what I started with. I didn't use as much glass as I was expecting, but I decided to not create a complete floor for the viewing chamber. The most interesting thing to note is the shadowing. If you watch carefully you can see how things keep getting darker as I got closer to the bedrock. I'm not sure what caused it, but the area where I first hit the lowest level (where I dropped the ladder) I could get a full view (as you can see from the viewing room) of the area. However, if I were to step about 5-10 blocks in any direction the darkness would close in. Once I got down to about level 12, I started having to contend with the slime spawns and fought them off as they spawned. I ended up with about 25 slimeballs from that. Once I got into digging out the trench I had some lighting issues and had a few endermen, zombies, and creepers spawn, which is why I ended up putting torches around the edge. After I put the water in, there really wasn't any worry about them, but decided to leave the torches there.
In case you're interested in doing something similar and want to know how to figure out where to dig, I used the Minecraft Slime Finder to pick the best place to find slimes. All you have to do is put in your seed (found by pressing F3) and then your coordinates, and it'll draw you a map of the surrounding area with the slime chunks highlighted in green.
ETA: Even though I cleared 9 chunks for this slime farm, only 5 of them are actually slime generating chunks.
After editing the video together and watching it, I see that I am going to have to be careful in the future to watch the things I say. Seemed that every time I started recording I said "Alright minecrafters." I'm still pretty new to this whole video thing, so I'm hoping you guys will stick with me while I get better at this.