4200, 5400, 7200, Oh My!
They did the same thing with the Gateway M505 series ... some have 4200 and some have 5400.
I dont think 5400 are the most expensive ... 7200 seem to be more expensive. Prices are $140 and $230 respectively. (July 2004, ZipZoomFly.com)
Seagate makes some 80GB and 100GB drives that spin up to 7200RPM. Before that, Hitachi was the leader with a 60GB 7200RPM drive. Of course they were 80GB out, but they were slower, at like 4200. (See Tom's Hardware Article
I suggest that everyone who has a slow 4200RPM drive get a faster drive. I've seen tests and even a 5400RPM drive gives a significant performance boost. Or if you want, just get a drive enclosure and drop a 74GB 10,000RPM Raptor in it. (Hard Drive Speed Tests
I would go for speed over space because the drive INSIDE your laptop is where the operating system and all your programs are stored. If you need space, you can always just add an enclosure.