You'll want one that grows in a rosette pattern. From what I have seen so far the Wendtii green gecko is beautiful and grows in the rosette, has purple, brown, green and red colored leaves. Looking at google images, I may actually not have green gecko as it seems to be mostly green in the pictures and mine is definately not but still grows roughly the same as the pictures I saw.
I'm still really new to crypts so have the basic starter plants. Wendtii in red, brown and green as well as a few others. Can't wait to get a few of the rarer colored ones.
From the plant database here - http://www.plantedtank.net/forums/my...Rosette_Plants
Cryptocoryne beckettii - really pretty
Cryptocoryne walkeri 'lutea'
Cryptocoryne wendtii - very happy with all my wendtii plants
Cryptocoryne x willisii 'lucens'
Cryptocoryne wendtii 'Tropica'
Cryptocoryne wendtii 'Brown'