the router I currently have I was quite impressed with as it's got different VLANs which will enable you to properly segregate that network, (not just give machines different addresses).
if you want a decent router, that is genuinely powerful, that you can configure to properly segregate and secure.
I'd look into an older brand making sure that it can run openwrt - preferably with a easy installation method. - but that may limit your abilities to get any outside assistance depending on who will support what.