Well, you just answered your own question. DO WHAT INTERESTS YOU MOST. Find projects that engage you and you have fun doing, and those are what you should spend your time on. I emphasize this b/c I tried to do lab research btwn 1st and 2nd year, knowing I wasn't really the lab type. Well, it was a miserable experience, my name never got on a paper, and I doubt I'll even bother to write it on my CV. I was doing it b/c I felt that I should, yet I expect I will get more noticed for doing the volunteer work I really enjoyed.
By the way, there are other, more fun, ways to get journal publications besides research - like getting in touch with a doc in the ER and writing up a case report on a patient. Some people really like research, but if you don't, don't feel that you HAVE to do it.