Netgear D6300 Wireless with Modem Router
Cisco Linksys X3500 - N750 Dual-band Wireless Router
Asus DSL-N66U Wireless-N900 Gigabit Router
Asus DSL-N55U Annex A
So basically a N600 to N900 adsl router would be enough as per your requirements. And mentioned companies are reliable. Specially Linksys, it has no issues of signal drop anywhere.