Rubystreak,
I’ll try to give what I understand to be a Jewish viewpoint on this story, based on classical Jewish sources.
The snake:
Jewish tradition sees the snake as an agent of Satan, who in turn is an agent of G-d (not a being who stands in opposition to G-d) with the job of tempting people to sin. (The issue of “Satan as independent actor” vs. “Satan as agent of G-d” has been covered in previous threads, but I’m too lazy to search for them.)
Various commentaries to Genesis 3:1 (Ibn Ezra, Ohr HaChayim, and others) explain that Satan found the snake most useful for this purpose because it was a sentient being, capable of “speaking” in a way that Adam and Eve would understand, and presenting its “arguments” skillfully (“the snake was more subtle than any of the animals…”).
So in short, the snake was chosen as the one most suitable for the role of a “devil’s advocate” - except that he ended up identifying too closely with his role. (It’s hardly the only case where someone has had the job of presenting a particular viewpoint while maintaining impartiality, and wound up becoming biased in favor of that viewpoint.)
The Tree of Knowledge:
One explanation I’ve seen - and I don’t recall the source - turns on the fact that the Hebrew word daat (knowledge) really means “intimate knowledge” (the same root is used in Genesis 4:1 about Adam “knowing” Eve). So according to this approach, the “tree of knowledge of good and evil” had the property of making good and evil inherent in the human psyche.
Put differently, when humans were created, their natural instinct was to obey G-d; it was possible for them to disobey Him and to do evil, but that was against their nature. Afterwards, by contrast, it’s more natural for a person’s instincts (some of them, at least) to clash with what G-d commands, and it takes a good deal of willpower to overcome this tendency. This was the situation G-d was trying to avoid by prohibiting them from eating from this tree.
But actually, the Midrash (Exodus Rabbah 32:1) notes that the prohibition on the tree was meant to last for only a few hours: Adam and Eve were created on Friday, and they would have been able to eat from the fruit of the tree on the Sabbath without any ill effects. [I don’t recall seeing any explanation for why this might have been so, although it might be that the added holiness of the day would have given them the strength to defeat this new evil inclination within themselves, much as a reinforced army can afford to lure the enemy into their ranks and defeat them there, rather than fighting the enemy on their own ground.] I also don’t know whether according to this explanation G-d actually informed them of this detail, or whether they were operating under the assumption that it would never be permitted.
In any case, though, this was indeed a test that Adam and Eve failed. Judaism posits that G-d created certain things in the world that are meant to be off-limits in certain ways - one purpose of this is to develop one’s self-control - and the Tree of Knowledge is the prototype of such things.
The prohibition and the warning:
The part about touching the tree wasn’t in the original instructions from G-d to Adam (see 2:17). The Midrash (Genesis Rabbah 19:3) states that Eve added this on her own, on the theory that it would be an extra safeguard around the original commandment (or, in a variant version, that Adam added this when transmitting the command to Eve); but that backfired, since when she did touch the tree (actually, the Midrash says that the snake pushed her against it) and nothing happened, that gave the snake an opening to deny the veracity of the prohibition against eating the fruit too.
Also, G-d’s instructions didn’t say that they would die on the spot after eating from the tree, but rather that they would die on that day, so the fact that neither of them dropped dead immediately doesn’t contradict that. I’ve seen a number of different explanations as to how this squares with the fact that both of them lived long afterwards; the most straightforward is that G-d was merciful and commuted their sentences due to their sincere repentance.
The realization of their nakedness:
The explanation I’ve heard ties in with the point that “knowing” good and evil means having them embedded in one’s nature. Before they ate from the TOK, their sexual drives were powerful tools whose normal use was for G-dly purposes, so the associated organs were no different than any other parts of the body; afterwards, that same sexual drive is (by instinct) attracted to forbidden purposes, so it’s necessary to tame it, part of which is accomplished by covering our bodies. (This is also why the Torah often equates holiness with sexual morality (as in Lev. 18 and 20): once such a powerful drive is under control, it’s easier to achieve G-dliness in other areas of human behavior.)
Blamestorming and G-d’s judgment:
Jewish tradition in fact faults both Adam and Eve for their attempted evasion of responsibility (and after all, as the succeeding verses show, they received their punishment too); a person has free will, and that includes the capability of blaming others rather than take the rap for one’s actions. (Adam is further criticized for his ingratitude in turning the gift of a wife into an excuse for his misdeed - “the woman that you provided to be with me gave me from the tree…”)
Nevertheless, the snake bears responsibility as an accessory to the crime. Indeed, the Talmud (Sanhedrin 29a) derives from this episode that when a person is on trial for incitement to commit idolatry (as set out in Deut. 13:7ff), it’s not a defense to say that the incitee should have known better.
The punishment of the snake:
Since, as I mentioned earlier, Jewish tradition sees the snake as a sentient being that chose to act in a certain manner, it’s only fair that it should be punished in such a way that it would never again be able to be an agent of temptation to humans. Part of this involved making it into a low and degraded creature (“you shall go on your belly and eat dust”), and part involved creating a natural antagonism between humans and snakes (“I will set enmity between you and the woman, between your descendants and hers”).
In general - and this applies to the following points as well - Judaism views G-d’s judgments as corrective rather than punitive: the punishment not only fits the crime, it addresses the “root causes” of the crime and attempts to prevent them from being a factor in the future.
The punishments of Eve and Adam:
One factor common to both of them is that they involve a lot of hard work and pain (child-bearing and -rearing for Eve, “working with the sweat of one’s brow” for Adam). The point is that keeping busy with these gives a person less time for improper or immoral pursuits.
As well, since Adam got into trouble by following Eve’s advice and eating from the tree, the corrective is that she should listen to him, in certain aspects, in the future. (As the Talmud (Bava Metzia 59a) expresses it, a man should defer to his wife’s advice in worldly matters but take the lead on religious issues.)
The expulsion from the Garden:
Now that Adam and Eve have gained an innate desire for evil (see above), the world would be a lot worse off if they went on living forever and remained in control of events. By making them mortal (and expelling them from the Garden before they could make themselves immortal by eating from the Tree of Life), G-d provides a chance in each generation that better people will take over. (Indeed, the Talmud (Shabbat 119a) calls schoolchildren the “Messiahs” of each generation - the ones who can be the harbingers of a better future.)