Rotor size inquiry

What size wheels you running? IMO get the best/biggest that will fit and you can afford...
15" rims. I was thinking the same thing that bigger is better, but how big is too big for my application? I mean, ANTHING is better than the manual drums that are on there now. Some guys will tell me 13" Wilwoods or Brembos are the way to go, and other will say that drums are okay. Just looking for advice from others that have done these swaps.