I would say the Panasonic E95 that is coming out. Otherwise the E100 is just as good. It doesn't use -RW but RAM and DVD-R. The E95 will be 750 at avland.co.uk. The E100 is around that price at the moment. I have a Panny HS2 which should be around £550-£600.
There are models from Pioneer that have a HD and do -RW. I prefer Pansonic or perhaps wait for the Sony HD models. But, they maybe some time off.
Once you have a HDD you will hardly ever use ram. I have not bought any extra apart from the 3 that came free with my hs2 over 18 months ago. I only use them if I want to temporarily store programs in a series off the hard drive until I have all the episodes to transfer in one operation to a -r. Indeed I don't even leave one in the machine due to the extra time it then takes to start up, merely inserting one to transfer to and from as required.
In effect a hdd works exactly the same as a ram disc, but you can store 8 times as much in the hs2, and 16 times as much in the E100 at any particular recording quality.