I like Core Servlets and JavaServer Pages, Vol. 1 by Marty Hall and Larry Brown. But if the Head First book seems too advanced, then I'm not sure this one will be much different. Then again, maybe it's just a matter of style.
In any case, you're likely to get better suggestions in the JSP forum, so I'll move this thread there for you...
"We're kind of on the level of crossword puzzle writers... And no one ever goes to them and gives them an award." ~Joe Strummer sscce.org