This is not the way to respond. This is biased, and thoughtless. All I have are PPC Macs, and I get by just fine. I have never yet owned an Intel Mac in my life. They just work, and I see no dire need to replace something that works.
PPC Macs can be very useful if you don't need the latest and greatest hardware or software. They can be extremely useful and cost effective if you're just doing some light work and internet use.
Not to mention, I watch ram for Intel Macs sell for "pennies more" than $220 daily.
This is a good, correct, and well thought out response. Consider this - if your needs include a lot of video play back or graphic intensive work, even the first Intel Macs beat out the last PPC Macs. If you only occasionally watch YouTube videos, and can wait for videos to load a bit, you'll be just fine on a G5, G4 or earlier. My opinion, though, is keep at or above 1.0ghz, but it's all in personal preference.