I second that, go with the power tower, I'm telling you!
I own an eMac and yes it works, and yes it works well, but the dark screen and GFX RAM issues WILL eventually drive you crazy and you'll be wishing (like me) that you'd had saved back a little and invested into a Tower instead!
One thing to keep in mind in the world of MorphOS is that it, unlike classic Amiga OS, REALLY does not play friendly with your Gfx RAM. Where the Amiga only needed 2Mb of GFX RAM to fly and get by, MorphOS will require 64 for most media related uses, it'll work with 32, but you'll be running out often. That is if you plan on having a bunch of programs and screens open at once.
Also with the eMac you'll want to run your system at a lower resolution, and if that DARK built in screen should die....
...well guess what, the Mini-VGA port on the side of the eMac is not supported by MorphOS so you can not use an external VGA monitor as a back up...
...you are screwed and have to order a new copy of MorphOS to use with another Mac (unless the MorphOS guys are willing to be kind and allow you to transfer your license.)
Just avoid it like the plague is all I can say. A Tower or a Mini with 64Mb of RAM don't cost that much and at least with those you are not forced to have a HUGE ass piece of crap monitor taking up precious space like I'm having issues with.