2 Separate Log Books
Having been flying now for well over 35 years, and having ATPL's from 5 different countries, I have always used one log book for fixed-wing and another separate log book for helicopters. Overseas you'll find that fixed-wing operators /airlines don't care much about your helicopter time, while helicopter operators worldwide may tend to recognize your fixed-wing background more so. You will also find that overseas, the local governing aviation authorities ie DGCA in India or the GCAA in the U.A.E. will want a separate breakdown/log of your flight time in either F/W or R/W before they issue you a license or validation. If you're logging time (or eventually plan to) in B737 and AW139 class aircraft as I have, you'll find it much easier to keep them separate, especially when dealing with licensing authorities overseas. Hope this helps.