It was a real lifesaver for me for the Gamedev Collection books. We had a lot of circle-n-arrow diagrams that were too low a resolution for print. I was able to redraw quite a few of 'em with Edraw and export 'em to high resolution TIF.
Actually if you did catch the freebie last time, you might want to grab it again. The August freebie was version 4.0, but this one's version 4.3.
Just remember that you must download and install the program TODAY. Part of the deal with giveawayoftheday.com is that their installers only work for the day that they present their daily freebie. So you can't just download the installer and install it later.
And it's legit. I've done several giveawayoftheday.com programs and have been very happy with 'em. There's no registration or ads or anything.
So don't miss it this time!
Oh, and somebody posted a list of a bunch of useful free stuff from Microsoft here. There's not a lot of really useful stuff here, but some of it is worthwhile.