My wife swears by 100% Egyptian cotton; she says Egyptian cotton linens get softer each time they are washed. She does go for sheets with higher thread counts. I think we are currently sleeping on 750 TPI.
300 count percale is what westin hotels offers as the "heavenly bed... It is achieved by down under the fitted 300 another 300 to your bod then a light weight summer down comforter on top... Never got to the beach last time I fell into one of those bad actors.... Well finally did... And duplicated the whole system at jc pennys for under 400.00 peace kr.