A multi-tool is a must for me. If you are looking for a new one do list out which tools you have regularly used in the past.

For me: pliers, scissors & screw driver pretty much do it. Occasional saw and tweezers. And knife! Interestingly my Featherlite was a 'blade as extra' purchase? And a week before my most recent trip the blade broke (at the hinge). Their policy of "you break it - we fix it" held true. It was returned in time for the trip. Warrantee is a factor worth factoring in.

+ buy the best you can afford. Cheap online is very different from cheap on the trail.