I've been running 8 speed Acera cassettes for the last 4 months simply because I ride rain or shine 1500-2000km a month. You wear stuff out fast that way and the difference in price between XT/XTR and Acera is.... rather large. They are both going to wear out in about the same time so I just go with the cheapest. Bling to me something totally worthless.

I am considering shifting up to 9 speed when the current chain and cassette wear out. Even then though I think I'll stick with a Deore derailler, a $35 9 speed cassette and a mid range chain.