If there had been any refurbished G5s at the online Apple store this week I'd have been sorely tempted to pick one up. iPhoto was being irritatingly slow last night while I was trying to work on the pictures from LeConte (so a machine eight times faster than my three year old but still quite stylish computer sounds very tempting). It actually got quite a bit better when I changed the size of the thumbnails though. I may need to experiment with that a little and see if it's got the thumbnails at a certain size cached and anything beyond that requires it to build them on the fly or if it's something else. That'd be a fine question for s4's Mac Genius buddy.
Even though I try to convince myself that a new computer would be much faster and I could deal with labeling/arranging/selecting pictures much faster, I doubt it would actually help. I'd probably still spend just as much time obsessing over minor details and making infinitesimal tweaks.