For Nikon or other camera equipment: I would use (and I do) the DeoxIT® Gold G100L-2DB brush bottle and the G100P Pen on any lens or camera contacts.
For any cables or connectors away from sensitive surfaces, I would use either one of the DeoxIT® D-Series sprays (my favorite is the DN5S-6N or DN5S-2N), and for gold connections, DeoxIT® Gold G-Series sprays (my favorite is the GN5S-6N or GN5S-2N)
For audio/video equipment: Use the DeoxIT® Gold G-Series on all gold surfaces, then use the DeoxIT® D-Series on all other non-gold surfaces.
Choose an applicator dependent on how sensitive the components or surfaces are. Usually, I keep handy one spray, one brush bottle, one wipe container and lint-free accessories. Sometimes the Pen, for harder to reach areas (computer DIMMs, boards) which also provides a little abrasive action on really dirty contacts.
Sample product recommendations (All are plastic safe):
DN5S-6N (or DN5S-2N)
GN5S-6N (or GN5S-2N)
DGN5S-2N (includes DN5S-2N and GN5S-2N)
K-DG100L-2DB (includes D100L-2DB and G100L-2DB)
K-AS10 (accessory kit)