I alway get car specific plates and leave them on the car - bonus perk for selling time whilst removing the 'new plate' stigma which I hate
S1 YLW on a Vegas Yellow Audi S1
W12 VRS on a Skoda Octavia VRS (Wife's nickname is Wiz)
RS03 WEE on the RS3
All were ~£400.
I tend to agree with D0C - someone will write a T on the end if the car is ever dirty!