I always here from people that the higher the thread count of sheets the better. But not all high thread count sheet are worth to invest on, there are few factors to be considered. One factor is the quality of cotton used, combed cotton is better. Another factor is the type of cotton, the best one for linens will be Egyptian followed by Pima. Feel is also another factor, what is a 1000 thread when it rough to the feel. of course it should feel softer to the touch.
Any linens that has 300 or more thread counts to it is considered good. Percale weave is usually 300-400 thread while 500-600 has a sateen weave which makes it feel silkier and has a softer texture to it.
If you are looking for wrinkle free or doe not wrinkle that much the best choice will be cotton-polyester blend. As long as its 300 threads and higher it will feel softer ans silkier to the touch.