For me, i've got a fairly cheap, 'tool set', can't remember from where now, but has set of screwdrivers, pliers, socket set and spanners, nothing special. Pretty much covers everything you need. Early needed extras I got that I can think of are a viscous fan spanner, the t55 mentioned above, square thingy for the diff plugs, 19mm spanner, circlip pliers, gease gun, torque wrench and of course a selection of hammers is essential.
Beyond that I think the list will grow as the jobs do. Electrical circuit tester, hub nut spanner, soldering iron, wielder and wielding tools, grinder, riveter, rounded off nut remover thingy,,,,, and on and on!
