A Beige G3 is not a very good choice for a first MacOS X machine. It will need extensive upgrades to perform well, and even installing the software will be difficult. Newer versions of MacOS X will require XPostFacto software for installation.
For a stock Beige G3, I'd recommend maxing the RAM, overclocking the bus, getting a flashed PC video card, upgrading the CPU, and getting a new hard drive, just to reach a minimum standard of productivity. Not really a project for the faint of heart.
If you just want the cheapest, easiest box to try MacOS X on for kicks, I'd look for a Blue and White G3. In stock form it'll at least run even the newest versions of MacOS X. Without any upgrades, the performance will certainly leave something to be desired, but it'll be really cheap.
For something more useful but still mostly inexpensive, you're right on about the G4s. Any old G4 with an AGP video card (avoid the "yikes!" G4 which is just a B/W G3 with a G4 card and different colored plastic) will be a much better MacOS X machine in stock form.
For just fooling around, get whatever's cheapest; if you want to get serious about running MacOS X on a G4, I'd recommend reading more about the specs at everymac.com, lowendmac.com, apple.com, or another site, and choosing your favorite. Whichever G4 you choose, there will be good articles in the archive at xlr8yourmac.com.
For a stock Beige G3, I'd recommend maxing the RAM, overclocking the bus, getting a flashed PC video card, upgrading the CPU, and getting a new hard drive, just to reach a minimum standard of productivity. Not really a project for the faint of heart.
If you just want the cheapest, easiest box to try MacOS X on for kicks, I'd look for a Blue and White G3. In stock form it'll at least run even the newest versions of MacOS X. Without any upgrades, the performance will certainly leave something to be desired, but it'll be really cheap.
For something more useful but still mostly inexpensive, you're right on about the G4s. Any old G4 with an AGP video card (avoid the "yikes!" G4 which is just a B/W G3 with a G4 card and different colored plastic) will be a much better MacOS X machine in stock form.
For just fooling around, get whatever's cheapest; if you want to get serious about running MacOS X on a G4, I'd recommend reading more about the specs at everymac.com, lowendmac.com, apple.com, or another site, and choosing your favorite. Whichever G4 you choose, there will be good articles in the archive at xlr8yourmac.com.