I think everyone would agree, there was nothing better than the original dual lands. And they weren't so broken, either! Of course, back then Taiga + Kird Ape was considered a "Killer Combo"... but times change
Anyway, thinking about it... there was just that many GOOD non-basic lands over the years... The best ones, of course, in Arabian Nights - Library of Alexandria, Diamond Valley, City of Brass, Bazaar of Baghdad, and, of course, my favorite - Island of Wak Wak
But after that - the only good non-basic lands we saw were Mishra's Workshop, Urza's Lands, Urborg, Thawing Glaciers, Kjeldoran Outpost, Lake of the Dead, Soldevi Excavations, Reflecting Pool... although with Urza's Saga there were Tolarian Academy, Gaea's Cradle.. maybe in the future we'll see some more great non-basic lands?