The two 20" models are at 2.4GHz and 2.6GHz, respectively. The former features 1GB memory, 250GB hard drive, 8x double-layer SuperDrive and a ATI Radeon HD 2400 XT with 128MB memory, while the later bumps the standard memory to 2GB, the drive to 320GB and the video card to a ATI Radeon HD 2600 PRO with 256MB memory (priced at $1199US and $1499US). You can also get a 750GB hard drive as an option on the higher-end 20" model (the entry-level maxes out with a 500GB BTO drive).
Here's where it actually gets interesting. The top-of-the-line 24" model features a 3.06GHz Intel Core 2 Duo processor, 2GB memory standard, a 500GB hard drive, an 8x double-layer SuperDrive and a NVIDIA GeForce 8800 GS with 512MB memory.
RAM maxes out at 4GB on that machine, and additional hard drive options (for both 24" models) are 750GB and 1TB. The starting price is $2199US.
Its slightly less brawny sibling offers a 2.8GHz Intel Core 2 Duo processor, 2GB memory standard, 320GB hard drive (500/750/1TB options), 8x double-layer SuperDrive and an ATI Radeon HD 2600 PRO with 256MB memory for $1799US. All models include both a FireWire 400 and 800 port standard and 3 USB ports.
If you've been holding off on buying an iMac, now is the time to flip the switch.
Thanks to everyone who sent this in!