The Barron's book is very good for the PAT, but don't even think about the other things in there. Kaplan is the main source for everything DAT. The only thing that I have heard about Kaplan is that it does not cover some parts of the plant characteristics, so you probably have to get Schaum's Biology or Cliff's AP Bio.
Just a thought and I want some feedback on this: my semester begins a week from tomorrow and I want to get as much studying done as I can between now and then. I was going to my balanced studying plan (Bio, Chem, Orgo all 1 chapter a day) but the thing is that I'm a Bio. major, so I have a lot of concepts fresh in my mind (mainly the bodily functions, having taken Physiology this past semester). In the week that I have left, do you think it would be a good idea to finish Chem and Organic, seeing as how I need to brush on them really well?