You need to find the tools which YOU like and can use best. As has been demonstrated with this CK kit people keep going on about - some like it, some don't, so you don't want to find you don't get on with CK stuff and have to replace the lot, or find you've got a load of tools you never use.
I would suggest buying basic mid range tools (pliers, hammer, sidecutters etc) such as Stanley or Draper, and as already suggested talk to the other guys you're working with and try their tools to see what you get on with and what you don't.
I could even say the same about screwdrivers - I mainly use a medium CK terminal driver which I think I borrowed off the caretaker when I was at school (so I've had it a while) and a medium pozi which I bought for 99p from Robert Dyas. Other drivers I have are a large slotted driver I bought from the local clearance shop for a quid, a small pozi and small terminal which I bought in a CK set which i rarely use the rest of.
I'm not suggesting these are the best or 'right' drivers, but they're what I use and like. It's down to you to find what tools you like.