Why Choose Dial Up Internet?

Pros:

It is most inexpensive Internet access option at the moment
Available almost anywhere where you can find telephone landline
Maybe it fits your needs? You don't do much youtube surfing or Internet video calling and need internet only to check your email, chat on Skype/IRC and read the news.
No long term contracts. Easy to cancel, switch, move on.
Great for traveling - you can dial from anywhere if there is local dial up number available.

Cons:

Slow. You might have trouble downloading all those windows security or antivirus updates.