I dunno... if you want to do any Photoshop rendering or other processor-based rendering, the lack of an L3 cache and only 256k L2 cache in the eMac could slow you up. The eMac has zero internal upgradability, i.e., processor or graphic card (you can add external Firewire drives to the eMac, however). Also, with all floating palettes and toolbars that the apps you want to use can have, I wonder if a 17" CRT (16" viewable) is gonna do the trick. If it doesn't, you're locked into THAT, too.
If you're on a budget, I suggest purchasing a recent used Powermac. Obviously the newer and faster, the better. BUT THANKFULLY, even an early AGP-based G4 Powermac would be a good way to go. Even though say, a G4/500 would CURRENTLY be slower than a 1GHz Emac (although it has four times the L2 cache and only 33MHz less front-side bus speed), it is much more expandable. Any Powermac, starting with a
"Sawtooth" design or newer, can be upgraded to as high as a DUAL 1.42GHz G4 processor (and higher, as time goes by)!
Also, you can not only upgrade the graphics card, but you can pair it with a monitor size that would befit your needs. You can get a mondo Trinitron CRT for cheap.
So, you could pick up a G4/500 with CDRW for about $950.00 (maybe less), a used 19" monitor for maybe $300.00. Make sure your ram is AT LEAST 512MB, and you'll end up paying about the same as the low-end emac with 512MB of RAM PLUS taxes. Down the road, you could get a single 1.2GHz G4 WITH 2MB cache for about CAN$485.00. A DUAL 1.4GHz G4 processor would set you back $1,557.00. That's a chunk of change, but they'll only get cheaper and faster over time. A Sawtooth G4, upgraded to a DUAL 1.4GHz G4, would rival a current single 1.6GHz G5; the current entry-level Powermac. And, you can move up to any speed at various prices at your convenience.
As a point of reference, I'm running the latest version of Mac OS X (called "Panther", version 10.3.1) on a G4/450. Window redraws are a little laggy, but the system hangs in there pretty good. I have to say, however, that I am considering a 1 or 1.2GHz upgrade. I cannot afford to purchase a G5, and it would be a dual G5 or nothing if i was going to go at all.
But hey; don't get me wrong; I think the eMac is a terrific value -- IF it suits your needs. I'm not sure that it does. others may hold a different opinion on this, and who knows which IS the best way to go? This s just the way I WOULD probably go.
Things i would NOT do include buying a slow G3, any beige G3 (because Aple has dropped support) and DEFINITELY DO NOT BOTHER WITH MAC OS 9. If you have to learn the ins and outs of ANY OS, you might as well go OS X. It is waaaaay more stable and hell, IT'S SUPPORTED. Apple has killedf support for Mac OS 9. NO upgrades will be forthcoming from Apple -- and most 3rd party software support is ending for it as well. The only advantage to OS 9 is that it will run faster on older machines than OS X will. But, according to many opinions out there, "Panther" has closed this gap, considerably.
In terms of system stability and resistance to courruption, Mac OS 9 = Win 95; you crash an app? REBOOT! OS X = XP; crash an app? Just reboot THAT APP. As for system crashes, two years running and I have NEVER HAD ONE. YMMV.
ANYWAY, that's my 2¢.