I would recomend buying OEM cables. I purchased a cluch cable from Dennis Kirk and wasn't very impressed. It's a smaller guage cable and longer than the stock one. I ended up having to re route it because of the extra length.
The Motion Pro clutch cable is nearly identical to the OEM cable for about half the cost. The one difference I could find is that the barrel on the lever end has a small metal sheath, that the motion pro did not. I'm not sure this will make much difference. Your dealer can get them through Parts Unlimited.
The Motion pro throttle cable had a slightly more serious flaw with the rubber boot that seals the top of the carb.
Of course, you can skip the whole cable thing and go hydraulic like I did. It is so nice, that I don't know how I rode without one for so long. I never worry about breaking cables or adjusting or having to deal with a sore left forearm on long technical rides. I use a Magura and I believe they are $199. IMHO, worth it if you ride a lot!