USB risers are anything but a waste of money. Unless you like annoyingly short ribbon cables for some reason... They are a $20 (well, less considering you still need $10+ ribbon cables) addition that makes the difference between a ghetto rig and a pro setup.
+1 I am planning in USB risers because
a) they will last longer because there is no flimsy ribbon cable for it.
b) they look better - The rig wont be a centerpeice, but it will hopefully be visually appealing.