Are GUIDs the ultimate ID?

I noticed some people don't bother having the usual incremented number as ID but instead simply generate a GUID. The advantages include:

• Quick and easy
• No need to keep track of previous IDs
• Guaranteed to be unique even across machines without knowledge of each other

Some disadvantages are:

• Possibly performance bottleneck
• Uses a large number of bytes

My understanding is that using a GUID is beneficial in most cases, except if optimization for time or space is an issue. Did I miss something? Or do you agree with this idea?

A couple of cons:

• Pain in the neck if you have to delve into anything manually (debuggin etc). They are completely unreadable.
• Horrible if you ever need to pass them in a URL