I use hickory with some oak or cherry.  Personally, I can't really detect a difference in flavor between smoke woods.  Maybe if I tried the same dish prepared with different smoke woods side by side I might, but I can't tell when I change it each time I smoke.
For me, the difference is how strong of a smoke taste you get.  Hickory is stronger, and I like that.  I'm doing a brisket tomorrow and I'll probably do mostly hickory with a little cherry.