I've got a 2006 Mac Pro that I've been working on fixing up, and I'm really happy with it. I've upgraded the CPUs to 3.0 ghz quad cores, found a good deal on an ATI HD 5770, and maxed out the RAM. It's running Yosemite now, thanks to some help from the good folks on this board. Despite its age, I think this machine could easily meet my needs for several years. So, if I'm bored and watching eBay for good deals on spare parts, what might be handy to have around? What is most likely to fail on this machine - the logic board, the power supply, RAM risers? Thanks in advance for any help.