StackOverflow is the website that changed my life the most. It's second only to Google Search. Google Maps is third. Facebook and Twitter could die tomorrow for all I care.
For me, Twitter is actually very usual tool for keeping up to date on industry news, blog posts, articles etc, I use it ONLY for work and not for personal stuff. Using TweetDeck, I find it invaluable (and I never thought I would before I started using it) since it let's be keep a watch on specific hashtags.
Do you mind if I ask how you are able to use Twitter to keep on top of stuff? I only really have HN and Reddit to keep up with work related news. I've never been able to figure out how to use Twitter for anything useful. It's total gibberish to me.
Not the guy you asked, but it's all about who you follow. You can't use Twitter like Facebook (i.e. "friending" everyone you tangentially know) without getting a useless flood of information overload.
Twitter is literally only as good as who you follow. You know the types that deride twitter as "Morons posting what they had for lunch" or similar? The answer is "don't follow people who post moronic food-based tweets".
Treat it more like an RSS feed with incidental two-way communication and you'll have a grand time.
Like Karunamon said, it's all about who you follow. I use Twitter exclusively for work, Facebook for personal use. Remember, Twitter is completely open, so think of it as an extension to your work persona.
Using Tweetdeck, I have a few columns set up, one displays everyone I follow, another few which aggregate specific hashtags. Since I work with a specialist piece of .Net software, I can have a column serve only tweets for that area. I had no value in Twitter before this and found out about more stuff relevant to me than through HN or Reddit. It does depend on how you use it, e.g. setting up a #aspnet search would likely yield to many irrelevant results, but follow someone like Scott Hanselman or Jon Skeet and you may learn a few crazy things!
I don't use Twitter the way it's supposed to be used.
However, I've found its search function useful for tracking breaking news. E.g., you can get to see the perp's mug shot an hour before the world does. Or pull up his LinkedIn before it gets deleted. Or find his Facebook page without doing the spadework yourself. You'll also come across random factoids that you can use to sharpen up your Google searches.
It's also useful for keeping up with certain technical areas. E.g., you can do a search on golang, scan through the results and happen upon stuff you might not come across otherwise.