i like SEO power suite which i am using since 3 years. its complete SEO tool for free. i found it very useful for the audit of my websites.

@OP: I've never yet tried woorank, but i use SEOpowersuite (enterprise license) and completely satisfied with seospyglass and ranktracker tool. Although it has free version.

Liam,

I doubt you are going to find a completely free tool that does everything you want it to do. There are a lot of smaller free seo tools like SEO for Firefox or the free versions of popular software but when you start wanting more, you usually have to pay.
Best,

Shawn

[DELETED]

[DELETED]