I always prefer cuffs on my heavier pants like flannels, tweeds, and tailored corduroy. I'm wearing some pearl grey flannel Rudys today and they look great cuffed.
Twill is a tough one though. If it's a pair I'm going to wear casually the majority of the time, I'd probably go un-cuffed, if it's a pair I'm going to wear to the office more often, I'd likely cuff them. For the steel grey twill, I'd probably cuff them.