I recall my uni days when I got an A for my essay but it made no difference to me because everybody else was getting an A from the same tutor. The point is, I'm not saying every post by a newbie deserves an upvote, because then the upvoting would lose its meaning.
I recently got a bad taste in my mouth from voting... I was looking at nodes I've written, and noting which nodes got the most XP. My second-highest upvote total was on a slightly funny and quite snarky reply I made. In contrast, I recently spent a good deal of my time writing a script to solve somebody's problem that I found interesting, and that work resulted in a meager 2 upvotes. Now maybe the low vote total is because most people didn't find the problem interesting enough to read the node, or maybe not.... It just kinda upset me that a non-helpful post can be rated so much higher than a genuinely helpful one.
All in all, I think the voting system works pretty well, though. It's a good way to engourage and discourage posts we like and dislike.