I totally agree that it's a matter of personal learning style. I kept my immunology, physiology, and biochem textbooks from undergrad. This semester, our course load requires books for immunology, physiology, anatomy, radiology, and histology... and the only books I bought were the 2 anatomy texts, which have come in very handy.
I refer to my immuno and physiology texts from college all the time, and actually think they cover the material much more in depth than the ones required for vet school. Rarely had a problem not being able to find the information I need. Once in a while, there might be one specific veterinary application that don't appear in my texts... but that's what google's for!
So yes! If you've already bonded with your textbooks during undergrad, then I'd definitely keep them. A lot of people don't even have time to read the required texts anyway, so even if they buy new books, many people don't get to know the books well enough to use them as effective resources.