What’s at stake? Theoretically, the whole ball of wax. The central issue is whether we as individuals have the "right to keep and bear arms", or whether we merely have that right as members of "the militia". The Second Amendment itself is kinda vague on this point. If the Court decides the latter, then it is possible that guns — even handguns — could be banned for any reason.
Let me put it this way — if the Court decides in favor of D.C., you will be hearing about "the Heller case" just as much as you hear about Roe v. Wade.
Again, I refer you to my earlier post.
Given the way the Court works, expect arguments in early spring and a decision in June 2008.
UPDATE: Here is the specific question before the Supremes:
"Whether the following provisions — D.C. Code secs. 7-2502.02(a)(4), 22-4504(a), and 7-2507.02 — violate the Second Amendment rights of individuals who are not affiliated with any state-regulated militia, but who wish to keep handguns and other firearms for private use in their homes?"
More background on this case at SCOTUSwiki
After a hiatus of 68 years, the Supreme Court on Tuesday agreed to rule on the meaning of the Second Amendment — the hotly contested part of the Constitution that guarantees “a right to keep and bear arms.” Not since 1939 has the Court heard a case directly testing the Amendment’s scope — and there is a debate about whether it actually decided anything in that earlier ruling. In a sense, the Court may well be writing on a clean slate if, in the end, it decides the ultimate question: does the Second Amendment guarantee an individual right to have a gun for private use, or does it only guarantee a collective right to have guns in an organized military force such as a state National Guard unit?
MY EARLY TEA-LEAF READING: Like so much else that comes across the recent Supreme Court, Justice Kennedy is the swing vote. And my reading of Kennedy is that he will deem this the right to bear arms an individual right, making the decision 5-4. I’ll even go out on a limb and say that Souter will side with the majority, making it 6-3. That will put the decades old controversy to rest.
Frankly, my research suggests this is the right conclusion. I’m not a fan of guns, but I think the Framers would have argued that it was intended to be an individual right, rather than a collective right.
What will not be resolved, at least conclusively, is the degree to which the federal government, states and municipalities can nevertheless restrict "arms" ownership despite the constitutional guarantee of a right to bear arms. I mean, I think everyone — including Charlton Heston — agrees that tactical nuclear weapons should not be availble at the local K-mart. The question is: where do you draw the line?