ddma - I would say either the 550 TI book or the 14inch ibook would be good choices. The 15inch ibook has a 100hmz bus which helps out. I wouldn't get a 12inch screen is I could help it. That is painfully small for my eyes. But I don't know what you need it for so it's hard to say. But if you can afford the TI 667, by all means get that! It rocks!
ksuther - sorry I disagree with your statements.
How is the 550TI a bad buy?

Yeah it's $500 more than the 14inch ibook but you get G4, combo drive, Gigibase-T, 1GIG MAX ram, better video(16meg DDR) and let's not forget a 15.2 inch widescreen

. It's also lighter and smaller. The iBooks's have G3, slower video, no 1000Base-T, MAX ram is 640MB, and smaller screens.
Also how do you figure the TI book is "bigger" than an ibook? A 12inch iBook is lighter by a 1/2 pound but you are comparing it to a 15.2 inch screen, smaller harddrive, etc....
iBook with 12.1-inch display
Size and weight:
Width: 11.2 inches (28.5 cm)
Depth: 9.06 inches (23.0 cm)
Thickness: 1.35 inches (3.4 cm)
Weight: 4.9 pounds (2.2 kg)
640MB MAX RAM
8MEG Video Mode
iBook with 14.1-inch display
Size and weight:
Width: 12.7 inches (32.3 cm)
Depth: 10.2 inches (25.9 cm)
Thickness: 1.35 inches (3.4 cm)
Weight: 5.99 pounds (2.7 kg)
640MB MAX RAM
8MEG Video Card
TI Books with 15.2-inch display:
Width: 13.4 inches (34.1 cm)
Depth: 9.5 inches (24.1 cm)
Height: 1.0 inch (2.6 cm)
Weight: 5.4 pounds (2.45 kg)
10/100/1000Base-T
1GIG MAX RAM
16MEG Video Card