Our current iMac G3 400mhz has 576MB RAM and an 8mb ATI Rage.
I'd get the eMac at least up to 512MB. I'm looking at either a 1Ghz or 1.25Ghz eMac.
The 1.25Ghz is a much better machine with 512k cache, PC2700 RAM and ATI Radeon 9200 w/ 32mb. The 1Ghz eMac has just 256k cache, PC133 RAM and a Radeon 7500 w/ 32mb.
People here have told me that Flash depends mostly on the video card, not the processor or RAM...