I've found some interesting interpretations of the meaning of Atalanta's name: Unswaying, Balanced, Equal in Weight; Equivalent To; and even Not Suffering Much.
There're basically two different versions of this character: an Arkadian [Arcadian] one and a Boiotian [Boeotian] one. The Arkadian was the daughter of Iasos and Periklymene (or of a certain, otherwise-unknown Mainalos - who bears the same name as another, more ancient Arkadian dude: one of the 50 sons of Lykaon, after whom Mainalos Town and Mt Mainalos were named, so I suspect that the name of Atalanta's father Mainalos simply means "a man from Mainalos"). After a race in Arkadia, she became the wife of the Arkadian prince Meilanion, who was her own cousin, or her father's cousin. The Boiotian Atalanta was the daughter of Skhoineus, son of Athamas and Themisto; after a race in the Boiotian Onkhestos, she became the wife of the Megarian prince Hippomenes. The Arkadian Atalanta's father had wanted a son and so was disappointed at her birth. He ordered one of his subjects to put her to death but the man tasked with this job instead took her up Mt Parthenion, the "Virgin Hill," and left her by the side of a well at the entrance of a cave. Shortly afterwards a bear, whose newborn cubs had been killed by hunters, happened by the place, took the human baby girl and suckled her. The same hunters who had killed the bear-cubs then stole the baby girl from her animal wet-nurse and raised her, naming her "the Unswaying One."
Apollodoros is the only ancient writer I know of who includes Atalanta in a list of Argonauts, and his Atalanta is the daughter of Skhoineus rather than the one who has a much broader mythology (although he claims that his Atalanta was also from Arkadia). Apollonios Rhodios' Argonautika says that Atalanta met Iason [Jason] at Mainalos, where she hospitably entertained him (perhaps because his mother was her cousin), giving him a spear as a gift in the hope that she might be able to join his expedition on the Argo. Because every other member of the crew was a man, however, Iason feared that strife would arise from jealousy over her, so he denied her enlistment to the group. After this expedition was over, Atalanta was generally received with scorn and hostility by the other hunters when Meleagros [Meleager] convened the Kalydonian Boar-Hunt. This wouldn't have made sense if she had, shortly beforehand, participated in the voyage to Colchis, because the individuals who were most vocal in their disdain of hunting with a woman were the Arkadians Kepheus and Ankaios, both of whom had been Argonauts. Nobody knew it at the time, but Ankaios was Atalanta's uncle and Kepheus was her great-uncle. Immediately after Atalanta had drawn first blood from the giant boar, Meleagros praised her aloud for it, asking his fellow hunters' acknowledgement of the feat. Ankaios then, in his over-zealousness to show himself better than this woman hunter, boasted that not even Artemis, who had sent the boar, could protect the monster from him, and he charged the tusked beast with his labrys (double-bladed axe). Though he was about as strong as Herakles, he was disembowelled in the process, failing to make it away from that encounter alive. In every ancient account of the aftermath of this story that I've read, Meleagros' maternal uncles were killed by Meleagros himself, either in battle in a civil war that broke out on account of the argument over the boarskin, or in a fit of rage for the same reason.
There is one version of Atalanta's life in which her concern was to avoid getting married rather than remaining a virgin as such, because the oracle of Delphi had warned her specifically against marriage. According to Ovid's Metamorphoses, the god of Delphi prophesied to her, saying: "A husband will be your undoing, Atalanta: flee from the necessity of a husband! Nevertheless, you will not escape, and, still living, you will not be yourself." According to some accounts, some time before receiving this ominous message, Atalanta had already lost her virginity either to King Talaos of Argos or to the war-god Ares. In one version she had a liaison with each of these guys in close succession, and from one of the encounters became pregnant with a son whom, upon his birth, similarly to her own experience in infancy, she abandoned on Mt Parthenion. Statius says that her devotion to Artemis began only after this event. Shepherds found the baby boy on Parthenion and raised him, naming him Parthenopaios, after the place at which he had been exposed. He grew up to become one of the Seven Against Thebes, who perished while trying to regain the throne of Thebes for Polyneikes. (Parthenopaios' brother Adrastos, another son of Talaos, was also one of these Seven and was Polyneikes' father-in-law.) As a result of Atalanta's encounters with both Talaos and Ares, no one was quite sure which of the two was the real father of Parthenopaios. Hyginus, however, claims that Parthenopaios' father was Meleagros, while other versions call him a legitimate son of Talaos by his own wife Lysimakhe, or even yet the legitimate son of Atalanta by her own husband Meilanion. Tlesimenes (one of the Epigonoi, who avenged the Seven Against Thebes ten years after the tragic battle between Polyneikes and Eteokles), who usually occurs as a son of Parthenopaios, is otherwise said to have been the son of Meilanion and Atalanta. Propertius seems to imply that the two Centaurs, named Rhoikos and Hylaios, who were killed by Atalanta had actually tried to rape her after she'd gotten married to Meilanion, and also that Hylaios had severely wounded Meilanion using some kind of a stick or club.
As retribution for Meilanion forgetting to thank Aphrodite for her assistance in acquiring his bride, once while she and he were out hunting on Mt Parnassos, Atalanta and Meilanion were inflamed with desire for each other, of which they relieved themselves in Zeus' nearby sacred grove. So Zeus punished the couple by changing them into lions, and the same story is related of the Boiotian Atalanta and her husband Hippomenes. Ovid's Metamorphoses has the Titan-goddess Rhea as the punishing deity, who goes so far as to yoke the metamorphosed couple to her chariot and make them the "steeds" of her vehicle. (In Ovid's story Rhea appears in her Phrygian aspect as the mother-goddess Kybele, who generally has a thing for lions.) Nonnos, the most recent of the mythographers to mention the story, is the one who says that Artemis was responsible for the transformation. The commonest (and maybe oldest version?) traces the metamorphosis to Zeus and his temple.