As an honest question (probably with some subjectivity), **how many smooth oriented 4-manifolds are actually symplectic?** Can I say half? I ask this question because every smooth oriented 4-manifold admits a *near-symplectic* form, i.e. a closed 2-form which is symplectic away from a finite set of circles.

Some results that might push the percentage one way or the other:  
1) Gompf has shown that any finitely presented group can be realized as the fundamental group
of a compact symplectic 4-manifold.  
2) The Seiberg-Witten invariants are nonzero for symplectic 4-manifolds, and in a sense show that they are the "irreducible" basic forms of smooth 4-manifolds.  
3) Every compact symplectic 4-manifold is a branched cover of $\mathbb{C}P^2$.