Where can I get old school floorboard nails?

[CoolHands]

I have to take up quite a few planks to fit sound insulation. I would like to nail them back down rather than use screws for a number of reasons: namely on other floorboards where I've used screws whenever you go back to them after a couple of years the head has got silted up with dust and they are hard to turn without slipping, and also hard to actually see! - they end up blending in. So I think using nails would be better - they don't get loose / squeak or whatever IMO as none of my original floorboards do so. Also I like the fact you can later on lever up the boards without having to run around and find all the screws. It's much easier.

So where can I buy / what is the proper name for floorboard nails? You kknow they kind of have a different head on them, a bit like a hammer-head shark IYKWIM?

Part of my floor (best pic I could find):

[CoolHands]

right I was initially going for nails. Then the argument swayed me to screws so I started looking at spax screws (£20-odd quid!); and now the pendulum has swung back to suggesting nails!!

I think I might now go for brad-cut-clasp nails ( ) if nothing else cos they're only a fiver!