Landing with all the crab on seems pretty foolhardy to me. There are swept wing types (B757 is just one example) which are designed to cope with huge side loads on landing - 40kt is the cross wind limit on that type. Frankly though, I am not keen on putting the theory to the test because I don't like drift in the flare!
I find it far simpler and much safer, even when flying the B757 in strong cross winds conditions to simply cross control on approach, it gives me much more control over whats happening with the added advantage of enabling me to land every time bang on the centre line. There are aileron/spoiler considerations for the swept wing pilots to consider before using this technique but that's another story! I use the same method when flying light aircraft.
Follow the FOH as one previous poster suggested every time, and adhere to cross wind limits but flying cross controls during the final stages of the approach will give you a far better idea of how much rudder authority you have left available well before the critical stage of actually landing the aircraft.
Well that's humble take on the subject anyway!