How to format text for normal reading

[user1]

I am using ubuntu 10.10

I have downloaded a lot of text files, both in text, html and e-mail 
format.

I have put a lot of files together using the cat command.

Then where it is html files, I have put some of those together using the 
cat command and then used the html2text command to format to text format.

Some of those files I have gotten have a verry bad format for reading, 
sometimes with strange strings mixed in.

I have tried sed and the sed users mailing list, but got no good replies.

So, my question is do anybody know some good and simple programs to 
format such text, so I can read it in my text reader (I am using leafpad, 
as I find it easy to use and good for changing pages when reading.)