XC boots - Style or NEW. Prolite are supposed to be very good, but i've not tried them. definitely something with rock-hard tendon and cannon bone guards, ideally something that doesn't cook the tendons, or absorb water!
i had my stud guard girth specially made by Pete Coyne in Walsall, very good quality, very reasonable. not sure if i've still got his number tho, might be worth a google.