Research has been very important and I would even say critical in my application for this cycle. It never hurts to get involved in research. Talk to some of your science profs to see if they know anyone who willingly takes on undergrads. If you find a lab, they might even end up paying you. I ended up getting 9/hr to go up and help out for a few hours a week. Not only did this give me some spending money, it got me a great rec letter from an eminent researcher, and allowed me to actually find out that I like research. You never know what will happen! I say its worth it to try getting a research job... but:
If you aren't into research, I would absolutely get a good amount of clinical exposure. Even if you have a great mcat, and a good gpa, if you've never stepped foot inside a clinic, it will come back to bite you in the ass. Volunteer for a few semesters at your University hospital, or find some shadowing time. Adcoms want to see that you've had clinical exposure and have some idea what you are getting into.
If you buy the MSAR, I think there is a section where it shows what percentage of accepted applicants at a given school have done research, volunteering. I could be wrong, but I thought I remember seeing that. Good luck!