Yeah I'm 50/50 on this too. Never really thought about it much for my car til I saw James Ford's 16V with them off, running dark grey #schmidt MLs, a US spec tail gate and jetta grille (page 108 of Performance VW June 09). I think de-arching can make a really clean line right round the car if the rest of the car and stance are right. Oh and BTW - he's kept his original gti side strips and not replaced them with CL ones and it looks fine!
So, er, yeah....well there really isn't a right or a wrong really is there??