Smell.
- Sight is needed for TV , movies and vidya.
- Sound is needed for music and important for the above.
- Touch is also quite important for games I'd say, amongst all the important stuff like knowing when something hurts which generally means you need to stop the cause from happening to stop the risk of damage.
- Taste is well, while not completely important, I love food and don't wanna miss out on bacon, curry and fajitas.
As for smell, sure some things smell nice and I'd be missing them but some things smell nasty too, yes some things taste bad but you just don't put them in your mouth.