I'd rather have a separate headlamp. Think of all the times you want light when you don't need to wear a beanie--or vice versa!

Also, for night hiking, I've found that can see the trail better if the light is down closer to my waist.

I use one of those little Photon LED lights as a backup light--it can be used anywhere, and I've found it handy when the batteries on my main headlamp run out (that never happens in the daylight!). With that and my headlamp, I don't need another light source, and both of them can be used year around.

Your Mileage, of course, May Vary.