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.