[Gmsh] Good 2D meshes

[Marco]

I have a problem. I am very happy with the possibilities of gmsh. It is 
really great but i find that meshes are absolutely awful !
With another meshers like modulef from Inria, the producted meshes have 
a very good quality. For my applications, i want to have
quasi-equilateral triangles and it is not the case with gmsh. So i want 
to know if there is special options in order to increase the quality of 
meshes.
The basic example is the following square :

lc = 1.0;
a = 5.0;
b = 5.0;

Point(1) = {-a, -b, 0.0, lc};
Point(2) = {a, -b, 0.0, lc} ;
Point(3) = {a, b, 0.0, lc} ;
Point(4) = {-a, b, 0.0, lc} ;

Line(1) = {1,2} ;
Line(2) = {2,3} ;
Line(3) = {3,4} ;
Line(4) = {4,1} ;

Line Loop(1) = {1,2,3,4} ;

// Ruled Surface(1) = {1} ;
Plane Surface(1) = {1};

Physical Line(0) = {1,2,3,4} ;

MySurface = 1;
Physical Surface(MySurface) = {1} ;

Waiting an answer, best regards