The higher the count, the softer they are supposed to be.
HOWEVER
I recently read an article in GOod Housekeeping online, I believe it was, that did their own research on many of the top brands of sheets, counting the threads, and found that many of them lie about the counts. So don't always assume that because it says its 1000, that it really is. You have to do some research on it to see.
Usually, if they are asking $59.99 for 1000 TC sheets, they're fibbing a bit =) High count quality sheets are very very pricey.
High thread counts should be very soft, and get even softer after washing.