Adjustable wrenches
Since I don't have many open end options I depend more heavily on adjustables. A 6" and 10" are the ones I use the most by far, though an 8" has become more used. (Little 4"ers are collectibles only, and 12" rarely get used by me). But get the wide-opening variety. That little extra bit of widening sure seems to come in handy.
Hex bit driver
There are so many different sizes and types of fasteners out there one would go broke trying to assemble a set of screwdrivers to fit them all. better to get a solid drive handle and then grab a nice set of 1/4" hex bits. How varied a set you get depends on your needs, but this way you can get Torx sizes, square for license plates, and hex to square adaptors for use with sockets. (I already frowned upon sockets in 1/4" drive as not as necessary as 3/8", but - with a bit driver - a sockets only 1/4" set would fill a big part of the bill for small fasteners.
Almost everybody makes a bit driver - I prefer ratcheting types.