Wow, there's some remarkably offensive stuff here, but i'll ignore it for the time being. The question here seems to be "Which race in D&D is least like the current idea of what defines human masculinity", especially since during the time period most D&D players base their fantasy on, it was considered the height of masculine fashion to wear tights and garters with pointy shoes.
Elves being non-masculine is all a matter of how you present them. The original source of elves in mythology was Norse myth, where they were strongly tied to both the Vanir and Aesir races of gods, their name even seeming to be considered a synonym for Vanir by some poets. Yes, they are described as being very fair, "as the sun" in fact; but there is little evidence to suggest they were seen as hairless or otherwise not masculine- Freyr, fertility god and the best-known Van, was said to be lord of Alfheimr, and he is consistently presented as having a full beard and broad, strong features. Himself often considered the source of D&D elves, Tolkien drew upon this mythology more than any other in creating his elves, presenting them as semi-divine beings of great power, rejecting other mythologies' concepts of frail fey elves (indeed, in most other sources, "elf" is often a synonym for fairy or fey, not referring to a particular kind of being).
Then there's gnomes, who many players gripe are not defined well enough to properly play. I have some trouble understanding this- gnomes in D&D seem to be very fey-inspired, presenting an option for players who like that attitude but do not enjoy the trouble of LA and such. They have a strong natural link to nature, innate powers of illusion, and a reputation for mischief- sounds like nearly every fey race in fantasy and folklore. It also doesn't sound either masculine or feminine, merely "other".
Next up are halflings, and if you think that being "homey" is enough to make someone feminine, then you might want to go back to the 1800s, and even then you should reconsider this opinion. Halflings are stocky tobacco lovers with thick body hair; an image that western culture has long considered masculine. Their love of home is tied up in Tolkien's own nostalgia; there was (and likely still is) a strong nationalistic undercurrent in England that promoted an idealized country life, and the hobbit culture is a solid example of that sort of living.
Half-elves? Well, see the paragraph on elves. I seem to recall some of the better-known half-elves were actually fairly swarthy folks, but maybe someone can provide me with a better example.
I think dwarves have already been argued successfully, so i'll skip that as well, except to note that a lot of people nowadays consider it unattractive for a man to have dense body hair of any sort, including facial hair.
People are pretty surprised by half-orcs having been voted for. While it might be someone's idea of a joke, let's take a look at that. Half-orcs are commonly presented as ugly, incapable outcasts with no culture and no skill other than brute strength. What's particularly masculine about that? There are a great many people, including some of the better fantasy and science fiction writers, who believe that a man should be bright, clever, and able to do just about anything that is asked of him. This is the "Competent Man" stock character, one of the best examples of which would be MacGyver. You want to tell me (or his legions of fans) that MacGyver isn't masculine? Heck, you want to tell Richard Dean Anderson that? While they aren't feminine by modern standards, half-orcs also aren't particularly masculine, unless you have a very dim view of men.
Last, and actually least for some odd reason, are humans. Well, let's see. Human beings have the largest mammaries in proportion to the rest of their body of any other mammal, the Y chromosome is becoming smaller and weaker over time, and considering that most people on this board seem to equate dense body hair with masculinity, the average human is pretty hairless. Our society increasingly declares that an attractive man has very little body hair, particularly no facial hair; as i noted before, it used to be fashionable for men to wear tights, garters, and pointy shoes.
