If you're using the text to display it in a browser, I'd store it with <p> tags. Why have to convert after selecting? It may eventually cost you another MB or two of storage space, but that's pretty negligible these days, and it will matter less in the future.
The main reason I would not normally do this is that you would then be adding characters to the data whose only purpose is for formatting in HTML, breaking the separation between view and model -- potentially adding complications to DB searches against that data and adding extra work if you ever want to use that data for purposes other than output to a HTML page.
Now, if you're pretty sure going into things that the only purpose for that data is to be displayed as HTML and either you won't need to search against it or are willing to deal with HTML tags in it while searching against it, then it would not be a big deal either way, I suppose -- but data tends to have a life of its own and is often more important than the application, these days.