Ranks.nl has a nice keyword performance & Density Checker tool which allows you to crawl a particular page and analyze the density of its keywords not only in the content of the page but also in the tags.
Compared to any other keyword tool, these tool gives you the freedom to play with a lot more variables that affect keyword density and prominence calculation.
Some of the extra features are:
- Ignore StopWords from default list or a list of your own
- Ignore keywords in Title, Meta Tags, Comments tag, Noframes tag etc.
- Case Sensitivity
- Allow ALT and Title attributes with single quotes ‘ ( as in alt=’something’ )
- Strip Underscores ( _ substituted by spaces )