Hi KasohiroNakamura,
You didn't tell us which aeroplane you are discussing, but, if its a modern jet airliner with high-bypass-ratio turbofan engines, you already have good advice.
The wing devices you describe as "speed-brakes" may need some clarification. In flight, some or all of them double as roll-spoilers. On touchdown, usually after main-wheel spin-up, they extend to a higher angle than possible in flight. In this mode, they are called "ground-spoilers" or "lift-dumpers". And that is their chief job, as vp1 clearly wrote. At high speed, with the trailing-edge wing-flaps fully down, the wing generates a lot of lift even when the nose is down, making the brakes less effective. Ground-spoiler drag effect is roughly proportional to the airspeed squared, so they are pretty useless below 80 kts. [Don't forget, the wing flaps also provide drag.]
Fan-thrust reversers are nothing like as effective as the old-fashioned "bucket" or "clamshell" thrust reversers of the 1960s. There is a very good reason for this. In the 1960s, the fans were much smaller, or even non-existent. So it was structurally possible to catch the entire exhaust output of the engine (N1 and N2 air), and deflect it forwards and about 45-degrees outwards. So, even at a restricted power setting, you got useful reverse thrust right down to a standstill. This was invaluable on slippery runways.
Fan reversers do not deflect the air very much forward - much more sideways. This means they are reasonably effective at high speed, because the speed of the aircraft vectors the air forward. But they are less and less effective as you slow down. The other snag is that ALL the non-fan exhaust is still generating forward thrust. By the time you are down to 60kts, the only advantage is that you are not getting forward thrust. So, at low airspeed, idle reverse is probably just as effective as full reverse.
To summarise:
On modern jets, particularly with carbon brakes, anti-skid brakes completely outperform the reversers, except on an icy runway (don't go there). And the ground-spoilers/lift-dumpers are mainly to help the brakes by putting all the weight on the wheels. For most landings, full reverse is noisy, fuel-consuming, can lead to debris being ingested, and wears the engine - for little benefit. Brake units are cheaper than engines. Idle reverse is usually the best compromise.
Turbo-props, like the Hercules, may be a different matter...