Laptops easily beat out cells and PDAs in screen size and keyboard usability, not to mention um... everything else with exception of portability.
If you're just posting to your blog, something like the P900/910 would do well. i haven't used the phone so i can't comment on it personally, but if the extent of your need for a laptop is "student use" -- word processing, MP3s, email, and light web browsing, you might be better off with a low-end laptop or a PDA and portable keyboard.