I'd recommend staying away from multi-tools; trying to install a water bottle cage with a multi-tool is exquisite torture. Get good sets of hex L-wrenches and combination wrenches to suit the fasteners on your bike (metric or fractional). You can take just the ones you need on the road, have well-fitting tools and probably save weight over a multi-tool as well. As mentioned above you can add tools as the need arises.

A good chain tool, well-fitting nipple wrenches and a good cable cutter are good investments.

I'm leery of Channel-Locks or Vise-Grips for bike work.