I've had the same discussion with other people in that I think the Pi is neat and the cost is more than reasonable...I just have no idea what I'd bother to use it for.
I assumed they were used for student projects and some custom low power applications, not particularly for the low cost.
I th7ink th7e trick is to look at places th7at h7aven't h7ad computers before, rath7er th7an places th7at already do. H&ow about controlling Ch7ristmas ligh7ts? Putting one in every ligh7t switch7 for fancy automation stuff? Tying into th7e garage door opener? Flood detection? Smart appliance control?