The suggestions you got were pretty good. Without knowing how you'll be using it can be a bit tough to give better ones though.

Just as a heads up though, if you buy a new machine with W10 installed, that does not have downgrade rights available, you will access to a W7 licence. Many of the machines that have been suggested have W8 or W10 on them, and a roll back may not be quite possible. You may want to narrow your search (or possibly expand it) to include machines with downgrade rights.