Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
SiteCheckerTool.com - Website Analytics & Tools
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
SEO PowerSuite - Get all SEO tools in one pack - download free edition of SEO PowerSuite and get top 10 rankings for your site on Google and other search engines!
Better Uptime - We call you when your website goes down
A1 Website Analyzer - Analyze websites and save data into XML, CSV etc. Extract data about internal linking and importance calculations, file sizes, download times, HTML validation errors etc. across entire websites.