Your question is highly dependent on the region in which you plan to work.
In general, specialties that involve intense physical labor and more exposure to older patient populations (med/surg, ortho, long term care, acute rehab, oncology, dialysis, pulmonary, etc.) often have higher employee turnover rates and will be easier to enter. This is partially due to society's overall negative valuations of aged people.
Since an extremely high value is placed on youth in America, the nursing specialties that involve more exposure to younger patient populations (pediatrics, labor & delivery, reproductive medicine, ER, postpartum, NICU, PICU, teen clinics, etc.) are coveted, have low employee turnover rates, and are usually far more difficult to enter.
Keep in mind that, due to the economy, some new grad nurses are not immediately able to find jobs upon graduation in certain cities and states. Sometimes more than one year passes before they land that first job, often in a specialty they never envisioned.