In general, 4-2-1 headers provide more power (& torque) throughout the power band, 4-1 headers provide peak power.

There's some exceptions (Hytech, Toda, Spoon, etc), but you won't be able to buy them for less than say $700 (But they're worth it). All the high dollar headers are 4-2-1, but that's an entirely different design.

If you plan on going on to cams & etc, I'd recommend a JDM DC 4-1. It posts power gains similar to the high dollar headers because it has a 2.5" collector. The downside, obviously, is that now you need a 2.5" cat and a 2.5" exhaust.

No real power comes until 4500 RPMs because well, its a Honda.