well, questions first:
are you a student? what will be the primary use of your laptop? what applications will you use?
what is your budget range? what is "super mahal" to you?
regarding centrino vs p4, centrino is basically a "powered down" version of the p4 that's lighter on the batteries, which is essential in a mobile device like a laptop. also, most centrinos come with a built-in wireless lan, which you can use with the loyola campus network. finally, centrinos generate less heat, which can be kinder to the other parts of your laptop thereby extending its useful life. all that in exchange for a higher price tag of course.
google is your friend in ur search for a good laptop, if you're not averse to reading. try typing "laptop buyer guide" as a search string.