The 12" ibook is a lot in a little case, but for the same $ (or less if comparing to 14" ibook) you can cobble together a faster machine with better video and superdrive, 15" monitor, wireless keyboard/mouse. You give up a battery and all-in-one design. If you only need limited portability--to move around the house and transport to other places occasionally (no classes, coffee houses or airplane use)--is the "new" mini w/ 1.5, 64, and 5400 drive a much better buy than either of the ibooks?
Yes, I have to say I agree. The Mac Mini's new specs sound like they match the 12-inch Powerbook, with the exception of the video card being different.
I'd take the 9550 in the iBook over the 9200 in the mini anyday, regardless of how much VRAM it has. If the upgrade is true and the HDD gets bumped up to 5400rpm, the GPU will be the only thing from stopping me, and many others, from buying a Mini.