So this is not very biological... And normally I object to seeing my face, but I had to share my elation at getting my MS this week! So for the 'biological-minded' considering grad school, I thought I'd share some advice which has helped me.
So, if you are a undergrad or returning student, one thing to do right now is get into a lab. This may mean that you have to volunteer, which is tough if your strapped cash, but necessary. Really, this give you valuable experience as professors are less concerned with grades as they are with experience. When it comes time for letters of reference, you also have a leg up on those who will rely on people they only know from classes. The need for cash can be alleviated, as once you are in the lab, funding and scholarships generally can be found. This will also give you a taste for what graduate school is like. So if you don't like doing research, better to find out now than two years into the program.
Most importantly, it's not the school, it's the person. No matter how much you may like the school's program, you really want to find some one whose research you are interested in and you get along with. You will be working with your advisor for 2 to 5 years, in closer proximity than you would work with someone on a job. So, do some research on them. What have they published, What are they working on now? If interested, you should contact them and meet with them. In many schools, you have to be accepted by the professor to get into the program, and they may not feel comfortable accepting you unseen. Also, this give you a feel for how well you might get along. You can talk with their students as well, but keep in mind what they say might be colored by how they interact with their advisor. (If your talking with them at a meeting, they may have spent the previous weeks being grilled by their advisor to get them ready, so they may not be feeling very charitable)
Finally, if you have a love of learning, go for it!