DNS failover solutions

DNS hosts - cheap w/ no failover:
- www.godaddy.com ($3/month)
- aws.amazon.com/route53 (pay as you go)

DNS failover services:
- www.dnshat.com ($20/month) has a very basic interface.  I felt turned off.
- www.totaluptime.com ($40/month) is a nice site.  Offers custom probing, email alerts, and how-to videos.
- www.dnsmadeeasy.com ($30/year for up to 10 domains) looks ideal for my needs.  Failover monitoring is an additional $5/year per hostname.

DNS failover software:
- www.simplefailover.com ($90/one-time, 14 day free trial) is an on-premise program that can monitor the availability of your domains, update them via DNS zone transfer, and email alerts.  It sounds pretty cool.