Need a suggestion for checking all URLs on a site

My company is doing a huge revamp which includes a ton of URL 301 redirects…problem is there are hundreds of thousands of URLs that have been out there for 10 years.

Whats a good web link validator tool. The company will be paying so money is no big deal.

I need some suggestions and any advice people have that have done huge websites before…

thanks

Yep agree, Xenu and also Google Webmaster Tools is very handy for catching crawl errors and 404s etc.