I use WebCEO. It is quite good for optimising pages and for checking the rankings of keywords in the search engines. Best of all I use the free version which is good enough my my needs. Try it out, like I said, it's free and if you don't like it, atleast it hasn't cost you anything
There isn't any good SEO software. If you want to get the best result you should avoid using any form of seo software. You can achieve far better results managing your SEO efforts manually.