I'm coming at you from my new, old Mac. I'm in the process of copying all of my photos over so I'm going to take a one day break from the photos while I explain what's going on.
A friend of mine at work is a rabid Apple fan. He's also a frequent upgrader. We were talking just yesterday and I described the current situation with my PC which, frankly, has not been a happy story. This is the same PC I put together just last April. In short, it freezes frequently. He mentioned that he had an older Mac that he wasn't using and made an offer I couldn't refuse.
So this new, old Mac is a G5 Power Mac with dual 2 GHz processors, dual 400 GB drives, dual head video, super drive, 2.5 GB RAM, etc. Not cutting edge but it works surprisingly well. I'd rather use a computer that is slightly slower but more reliable than a fast PC that freezes, quickly. So far so good.
I've got Lightroom and Photomatix installed on the Mac and ready to go. As soon as the however-many-gigabytes of photos finish transferring long after I'm asleep tonight, I'm set to go for now...