Good thing, because one would not want to accidentally trigger Hardmode. (By the way, where does that term come from? Is it used anywhere in the game?)

"Hardmode"? From the 1.1 patch notes:

As WingedKagouti has said, fighting the WoF takes considerable time, especially the first time you try it.

This here is a picture of my first world. You can clearly see the two stripes of Hallow and Crimson which where sprouted on the verge of death of the Wall of Flesh. It seems I finally got the Boss directly left of this one obsidian tower between those stripes. And as you can also see, this took me about half of the span of this world. I've started the fight on the westernmost part of the Underworld.

This world was spawned in version 1.2.0.3 iirc, it is medium sized. The picture was taken with TerraMap.

More like "happy running away while shooting backwards". :P

E: While we're at it, use jester arrows - all these little guys wont prevent you from hitting the boss.

Thanks so much, and since you are here, one more really minor preferential question. I look at everyone's creations and don't see any prep for the NPCs that arrive in hardmode. Am I missing something but wouldn't it be wise to build for more that the (15 I think it is) pre-Hardmode characters?

There are 7 Hardmode NPCs, one of which is seasonal and one requires a house in a mushroom biome. This means that most houses, villages or however you've organized it will only require 5 more standard dwellings than pre-hardmode (given that you've acquired all 15 pre-hardmode NPCs). As far as getting those 5 hardmode NPCs, 2 require rescue while the other 3 require progress in hardmode.

Thanks, I'll try to keep the stupid questions to a minimum. :P

Just a thought; given how the developers keep nerfing methods of killing the new final boss, I suspect that speedrunners who want to kill it will prefer using earlier 1.3 versions.

What they've nerfed in regards to the Moon Lord:

* Leeching (Vampire Knives/Spectre armor using Hood, 1.3.0.3) - Not used for speed, but for safety. Also, both of those do fare poorly against the Moon Lord's own leeching ability due to their lower damage.

* Damage Immunity (1.3.0.5 & 1.3.0.6) - I don't think anyone caring about speed runs is going to accept immunity cheesing as a legit tactic. You might as well be using an infinite life hack at that point, because that's what those tactics basically achieved.

* Teleportation (1.3.0.4) - People were using teleportation to get to the Nurse to heal up and then rush back to the Moon Lord before it got close enough to endanger their NPCs. Any pre-1.3 boss (except Wall of Flesh) would despawn if you attempted that. Now the Moon Lord can teleport to any living player if it is not engaged in battle. Instead people relying on that tactic are just using an arena with small safe houses for the Dryad (+8 armor buff) and the Nurse.

And that's it. So, they've shut down what essentially boils down to a cheat, made people not rely on the safety net of leeching and forced people to stay at the fight.

I might agree on this point, since vampire knives would likely be more useful for healing off normal enemies. (Remember, in a speed run, taking time to heal is usually not a good idea.) On the other hand, safety might allow one to kill the boss with weaker equipment, saving the time it takes to obtain that equipment.
Actually, from a speedrunner perspective, anything is legit unless the speedrunning community has agreed to ban it in a specific category. It is not that unusual for players to take advantage of immunity, and in some games (can this be useful in Terraria?) players will get hit deliberately to reach otherwise unreachable spots.

Some speedrunners of console games have gone as far as tricking games into executing arbitrary code in order to trigger the ending as fast as possible. (Try searching for "Super Mario World credits warp" for one example.)
Being able to use the Nurse during the fight means you only have to be able to survive one hit and not have to obtain the equipment and health that would be needed to actually fight the boss. It would also make it actually worth getting the Nurse. (I have seen at least one speedrunner go out of his way to not have the Nurse spawn so that the NPC that sells explosives would come faster.)

Of course, there is one interesting question: could you trick the Moon Lord into teleporting somewhere dangerous? (Does Lava hurt the Moon Lord?)
Of course, none of the speedruns I've seen actually continue past the Wall of Flesh.

By the way, some speedruns are very different than non-speedrunning (what the speedrunning community calls "casual") play of that game, such as Baldur's Gate 1 and 2 speedruns.

There's a vast chasm between "I'm going to be immune to anything any boss does" and "I'm using combat knockback to reach an otherwise unreachable location".

And there are no locations you can get to faster with non-standard means (ie. not walking/flying/digging) in Terraria that will have much meaning. If you attempt to enter the Dungeon before defeating Skeletron you'll face Dungeon Guardians who are likely to kill you instantly if you aren't specifically prepared to fight them (and Dungeon Guardians are the currently toughest entities in the game). While you can access the Jungle Temple through various means before defeating Plantera, that won't do you much good as the Golem can not be summoned until after Plantera has been killed. To me that is no different from just running the ending cutscene via a media player (or watching it on Youtube) and claiming that means you did a super fast speedrun. Seriously, injecting code to skip (gameplay) sections of the game is not the same as actually completing the game.

Sure, it's not that trivial for the first person to make that kind of code, but that doesn't mean much in the way of an actual speedrun. Different types of accomplishment. Like any other flying boss the Moon Lord ignores lava and other terrain features (though terrain can block some attacks). And there's no location you could teleport to during the fight that you couldn't reach before it spawns, as it takes 1 minute after the last Celestial Pillar is destroyed for the Moon Lord to spawn.

There are plenty of ways to leave a dungeon and get back to your spawn point. Are there any ways to go directly from your spawn point to where you previously were? I'm getting a little weary of running all the way back to where I was looting when my inventory filled up. It would be great to be able to, say, drop a marking token and recall to it.

I know that in Hardmode there's an NPC that sells two-way teleporters. I'm wondering if there's a non-hardmode alternative.

It's not perfect, but before I hit a dungeon I snag a 2nd bed and make a tiny hut in front of the dungeon entrance, complete with the bed and a chest or two, and make that my spawn point. Now it won't get you back to your base but if you get killed at least you don't have to haul your ass all the way back across the map.

On another note, to anyone who might know, now that banners come with a specific number of kills, does that apply for the user or each character. What I mean is, if I get a Blue Slime Banner with one character, and then start over with a different character, does it give me another banner with I hit 50 with that?

Thanks. What I was more worried about is if I get the banner, start over, but because I as the user got it once I can't get it again and thus have lost it forever. Obviously that isn't the case.