Best prepaid offer that you have ever seen?

[PhotoJim]

This is a boring normal thing, but it's still a good deal:

T-Mobile US: put $100 of airtime in your phone, get 10 cents a minute including on roaming partners (in the US), including nationwide long distance, and a year of validity. Future topups, even for $10, also last a year once you've put $100 in the phone.

Great for low-usage people, also great for heavy-usage people because of the low rate.