heat generation during mixing of water and methanol

[HW Mueller]

DR, I was talking about the energy involved in forming a H-bond, medium effects, other bond formations, breakages, not included. All stable bond formation energies are giving the lowering of energy due to the formation of a stable bond. In other words, if the bond holds, it is because it has lower energy than the separated species.

[H.Thomas]

This is right if you replace 'energy' by 'Gibbs free energy' (G). The minimum of G determines the direction of chemical reaction. G is a combination of enthalpy (H) and entropy (S): G = H - TS.
Less G does not neccesarily mean less enthalpy, so there reactions that are endothermic. If we talk about solutions, try dissolving ammonium nitrate in water.

[HW Mueller]

Bond energies more or less are enthalpies, depending on how they are determined. If a stable bond forms energy is liberated (exothermic). One should not confuse an overall reaction between some substances with an isolated event like bond formation or breaking. An overall reaction may include bond breaking, bond formation, entropic effects, solubility effects.....
The overall energy change of a reaction is the free energy (positive or negative (depending on whether the reaction requires or liberates energy), that of an isolated bond formation/breaking is an enthalpy (positive for stable bonds).