In reply to Flinticus:
I have stripped quite a few floors now. This site is fantastic for advice and guidance.
http://newellwoodworks.co.uk/index.html
As he suggests I:
1. Clean between the boards and if possible lift and stack them tight together (when I lifted mine i put insulation under as well). Screw the boards down with good quality screws to hold them tight
2. I use wood splinters and lecol (see the site) mixed with sawdust as a filler for the gaps between boards and cover the screws.
3. Sand the floors best way you can (I hire sanders and use my own hand held ones for fine finishing)
4. My personal choice is diamond hard varnish. I use the sponge mop applicator, at least 3 coats. It gives an amazing finish and is incredibly hard wearing. I can't be doing with waxes that need redoing constantly. Lots of people including tradespeople have commented on the quality of the finish.
The cost of varnish, lecol, sanders would be close to some of your quotes I suspect. 2-3 days work for me solid.
Make sure you know what you want and what they will provide.
Good luck!!
Toby