Some PSUs come in both Modular and Non Modular configurations (Corsair comes to mind immediately, but there are others). The Non-Modular configurations are generally only marginally more expensive. As far as reliability goes, true, you can spend less on a Non-Modular 80+ Gold, but Reliability and Efficiency isn't so much of a problem either on Modular ones if you purchase a good one.
Gee Bee makes a good point though - Shop for what best fits your price range. If you spend your money elsewhere on the machine, you can save a few bucks and still get a pretty good non-modular power supply and push those extra savings to your other components.