Okay, because my flist is going crazy over this, and I've already written three identical comments, I'm just going to say it here.
I understand everyone's upset Snape died. I don't like it either, even though I predicted it, like many others, right after HBP. I cried about it (not while reading it, strangely, but afterwards I shed a few tears for our beloved greasy bastard).
But to say that his death was pointless, served no purpose, and did not strike a blow against Voldemort, I'm gonna have to disagree. Very strongly.
Snape's death directly helped end the war and defeat Voldemort. In fact, without his death, who knows how long the war would have gone on and how many more lives would have been lost.
Why?
Because Snape's death made Voldemort believe he was now the master of the Elder wand (no matter that he really wasn't), and thus he was now willing to take on Harry directly, and thus Harry was given the chance to defeat him.
Snape's death was a turning point in the story! Before, Voldemort was hiding out, because he still wasn't sure if he could defeat Harry. He had the Elder wand, but it wasn't performing as he expected. He didn't participate in the battle at all, he didn't seek out Harry to kill him, because it was too big a risk for him.
But in believing Snape was the elder wand's master, and in killing Snape, Voldemort made his biggest mistake of his entire Dark Lord career. And it is this mistake that allowed Harry to defeat him once and for all.
Honestly, without Snape's death, Voldemort might well have had time to create more Horcruxes, and then Harry would have had a real problem. But no, with killing Snape Voldemort was finally convinced he could kill Harry.
I'll say it again: Snape's death directly helped defeat Voldemort and end the war, and that is gives it a very real purpose.
I'm also intrigued by the way Voldemort killed Snape. He didn't just AK him on the spot, which is more or less Voldie's trademark. No, he didn't even do it personally, but instead ordered Nagini to do it. And he says he regrets it, and you know what...I believe Voldemort really did. Well, for as far as a soulless bastard like Voldie can regret anything. Snape's death was very personal to Voldemort, so personal in fact, that he didn't do it himself...and I think that's, in a very bizarre way, Voldemort telling Snape that he is more or less sorry he has to do it.
That's why I liked the way he died...it helped defeat Voldie and end the war, and it was an incredibly personal thing between Voldie and Snape.
Mind, I'm not happy Snape is dead, but his death wasn't a waste at all, and it might not have looked heroic, but even what seems to be a meaningless death can serve a very real purpose. And I think that is what JKR intended with it in the book.