I've been a big fan of Adobe Photoshop Lightroom ever since I bought Lightroom 2 a few years ago. It's been a great tool for organizing our photos (keywords! Color labels! Smart Collections!!) and also exploring post-processing through the Develop module. It's probably one of the smartest photography buys I've ever made (along with my DSLR and 50mm lens, though Zach's the one who picked those out).
Then the other day, Adobe released Lightroom 4. I played with the trial and at first I didn't notice much that was very different or special. But then I started noticing little things that seemed pretty great (go here for some short videos explaining the new features). The one that struck me the most (and which may have actually been mostly an upgrade from Lr 2 to Lr 3, but still-- it's an upgrade for me now) is the Noise Reduction tool.
The main complaint I have about my current camera (Canon 30D) is the "noise" (graininess) that shows up when the ISO is set too high. And since I'm often taking pictures indoors and of constantly moving children, I do a lot of shooting at ISO 1600 (the highest setting on my camera. Apparently they go up to like 500,000 now or something). Lately the extra noise in many of those photos has been buggin me more, and is the one thing that makes me want to upgrade cameras. So to have a decent way to easily lower noise in the photos that need it without spending a lot of money on a new camera is pretty darn exciting.
Here's a sample of a photo I played around with. They're both edited the same way, except the top one doesn't have any noise reduction:
So I went ahead and upgraded, it seems a worthwhile splurge and a fun "new" purchase to help me in my goal to make time for photography more often. Should be fun to explore the new features more fully. BTW it's $79 to upgrade if you have a previous version of Lightroom (with previous versions it was $99), and to buy new it's only $149 (used to be $300!). Again, I swear this has been some of the best money I've spent.