Several schools of thinking here. Many opt to stay with exactly what the engineers at Suzuki designed. Others feel the need to make a good thing better, and the intake tinkering can go from mildly tweaking the stock CV carb to opening up the airbox and/or switching to a flatslide pumper. And if you're so inclined, do-it-yourself fuel injection is on the horizon, thanks largely to the relentless efforts of mx_rob.
Intake-wise, what's worked for you?
-STOCK CARBURETOR [MIKUNI BST40] MODIFICATION
-MIKUNI TM-40 [HSR-40]
SUZUKI DR650SE INFORMATION INDEX
"...choosing a DR indicates an affinity for peace, harmony and enlightenment. Serenity lies in accepting it as it is, changing what you want, and the wisdom of knowing it ain't orange." -psmcd