Seriously… Can the iPhone or the iPod Touch replace your laptop for your mobile computing needs? What about just some of them? Two respected technology gurus (whom I greatly respect) have posted articles on this very subject.
Ernest Svenson a/k/a Ernie the Attorney recently traveled to Panama, and he decided not to take his laptop with him and to rely on his iPhone instead. His article discusses the email, phone, and applications aspects in detail. Ernie concludes that while he would not forego his laptop, it was reassuring to know how much could be done on the iPhone.
Dennis Kennedy has also written a series of articles analyzing whether the iPod Touch can serve as his secondary laptop. Dennis walks through his thought process in analyzing his needs and wants on this issue, and it is a very interesting read.
Sources: "Can You Travel Without a Computer, And Just Take an iPhone?" by Ernest Svenson, published at his Ernie the Attorney blog, and "My New Laptop Computer is an iPod Touch" by Dennis Kennedy, published at DennisKennedy.com.