Glad you're up and running with core.
Core offers even more flexibility than base as it is really a live, installable debootstrap base with some apps removed and others added ie locales. Once installed you have the base for a cli only box if you have very low RAM and CPU power as drg has (see this link antix-m8-5-486-on-old-hardware-t2336.html ) or to install whatever desktop environment and apps you choose from the Debian repos (Testing or Sid or -when squeeze goes final- stable)

The only apps from MEPIS is the kernel and the mepis-gfxboot file, both can be replaced if user wishes to have a 'pure' Debian.

Yeah, my LXDE and XFCE desktops are really fast, right up there with the base system in responsiveness. I went out and grabbed Google Chrome and created a few Web applications on the desk, so it was fun playing with it. I have to move on to other stuff right now, but the experiment is looking good, and I am glad you told me about the use of the cheat codes. In future updates, we might want to have multiple menu entries with descriptions of what the various choices are - I think you did that in the past on one of the earlier releases - and maybe all of the Live CDs. I'll have to go back and look. In any case, I am on the air and it looks very good!