The largest avatar here is the minotaur. He's hunched over and pushed to the background of this group shot, but he towers over the others at 8'8"/263cm when standing up straight. Mythological minotaurs are usually depicted as being anywhere from 6' to 9' tall. This is similar to the range in Tauren heights in World of Warcraft.
What's remarkable about that is that the SL avatar mesh maxes out at the same exact height, and a lot of male avatars in SL do exactly that! So the hulking giant in this screenshot is only the size of the tallest "normal" human avatars in SL. With the average human male avatar in SL being anywhere from 7'1"/216cm to about 8'/244cm, the minotaur isn't very imposing at all when tossed out into the grid at large.
To take that comparison further, the human woman on the right is only 5'7"/170cm (although her high heeled boots push her up to 5'11"/182cm which is taller than the average North American man, unless he is also wearing 4" heels) and would be considered a dwarf compared to the 6'4"/193cm female starter avatars LL provides to new users.
This means that, just using the base avatar mesh and no tricks, we could create an almost 9' tall giant which would stand eye to eye with the minotaur pictured here. Giants in mythology are generally depicted between 7' and 11' tall. The giants in Skyrim are also "only" 11-12' tall.
Enabling people to create intentional giants is not a new argument from me, so then what exactly is the point I'm trying to drive home, here?
Well, the most often cited counter argument I hear is that the flip side of making human avatars human sizes is that we'd eliminate the ability for people to create intentionally shorter avatars, like, for example, dwarves and goblins.
To that I say that the dwarf and goblin avatars in the first screenshot of this post clock in at 5'/152cm and 4'9"/145cm, respectively. The female dwarf shape I also include in my free shape set is also 4'9" and neither is the shortest I could have made them.
It is difficult to maintain adult human proportions under 4'11"/150cm, certainly, but when you aim for dwarf and child proportions it becomes much easier. In reality this is true as well, as a 5' tall adult has notably different proportions than a 6' or 7' tall adult.