Huh?? What you mean go from router to a computer???
Cause most of the router has a switch built in, which mean the connection is just like hub/switch to computer and that needs straight cable.
BUT dont confuse with the uplink port on the router. So if you use that uplink port to connect to a computer (its like you dividing the whole network into small division) then you will need a crossover cable.
hope that helps,
MameXP,
PS. also in future dont use the term normal for straight, i getting hard time to figure out that

j/k. There are only 3 type for the cat5 cable: rollover, crossover and straight(thankx OSUmax for reminding me)