I personally like to use http://www.woorank.com they give you a comprehensive look at your website and will even give you a PDF of it.
take a look at this one too: http://urloz.com seo+sem for any url, estimated traffic and value, google page rank, alexa rank, search engine backlics, code analysis, keywords ckecker!
i just use seoquake plugin of mozilla browser... it works... Eventhough we can see many parameters of website arrived, like Page rank, alexa rank, etc..
These tools are only usefull for looking up website statistics, but the website value is usually way off. Most of them also dont include the value of the domain itself. I have tried a bunch but the values varied from 3000 over my personal estimated values to 0 :/
that's the idea reyuken! statistics! it's very hard to get a real value! there are to many variables! for example i read in another thread that pizza.com was bought for 3.000.000$! that websites has now something like 400 visitors and 200.000 in alexa, the estimated value can not reach that amount of money! How much would you give for a website who has that traffic??