I suggest the M760 crankset, strong, relatively light, not outrageously expensive. It's hollow design makes for a very stiff crankset and very high strength to weight ratio that can't be matched with "solid" cranks, such as middleburn. They also have a much better interface than the Race Face cranks, no plastic preload spacers, only two small bolts that you have to undo to get the entire crankset off, vrs the race face which still uses a taper interface and a huge 14mm bolt to secure it (it's a self-extracting bolt, but getting it off takes a lot of force and even though it's slight, you're wearing the interface everytime you uninstall it). I abuse the heck out of my bikes and components and it's held up very nicely.