Smell and taste are pretty closely linked, so I'm not how well one would work without the other. That being said, I'd rather lose my taste than my smell. For example, I'd still notice smoke or toxic fumes right away, rather than not noticing and possibly harming myself because of it. Taste, though, might even be a benefit, as I'd gladly eat things that I may not really care for right now (I'm looking at you, brussel sprouts).
Of the other three senses, I'd prefer to lose hearing, touch, then sight in that order.