BOL

The answer depends on whether you are talking to a computer scientist who does' biology or a molecular biologist who does' computing. Most of what you will read in the popular press is that the importance of interdisciplinary scientists cannot be over-stressed and that the young people getting the top jobs in the next few years will be those graduating from truly interdisciplinary programs. However, there are many types of bioinformatics jobs available, so no one background is ideal for all of them. The fact is that many of the jobs available currently involve the design and implementation of programs and systems for the storage, management and analysis of vast amounts of DNA sequence data. Such positions require in-depth programming and relational database skills which very few biologists possess and so it is largely the computational specialists who are filling these roles. This is not to say the computer-savvy biologist doesn't play an important role. As the bioinformatics field matures there will be a huge demand for outreach to the biological community as well as the need for individuals with the in-depth biological background necessary to sift through gigabases of genomic sequence in search of novel targets. It will be in these areas that biologists with the necessary computational skills will find their niche.

I am a bioinformatician, and love to explore biology with computational tools. The fact that bacteria can store more information than a giant 900 terabyte hard drive can fascinate anyone to join biology and understand the complexity. I personally think It is easier to move from computer to biology for resarch perposes. You only need to learn your basic of biology and indepth of your reseach area. 

I personally moved from biology to computational biology sector and loving it. Computer science is much more easier that complex biology, you only need to improve you logical thinking to run your dry scripts!!!!

Note: I mean biology to bioinformatician/computational biology not computer scientist ;)