It is worth looking into air coolers if you only want a single card. If you're looking at SLI and heavy overclocks / very low temps then liquid is the only real way to go other than stock cooling, but the big 3 or 4 slot coolers work so well, they'll match any 2x 120 radiator. You'd need a monster 3x or 4x 120 rad to beat them. It's also much cheaper to get a £50 cooler instead of a full loop, so yeah - worth having a look around.
As I say though, if you're ever looking to have two cards, the monster air coolers cripple your choices for motherboards as you need the two PCIE slots about 5 slots away from each other! lol