Can the density of a liquid affect its viscosity?

I'm not entirely sure on your question. But if you're asking if there is a direct link between different liquids, then no, there isn't.

Generally, density and viscosity both decrease with temperature, so they can be linked that way within a single liquid.

To illustrate the difference between liquids I offer you an example:

Mercury is only 1.4 times more viscous than water, but is 5.4 times more dense.
Glycerine is 15 times more viscous than water, but is only 1.2 times more dense.
(~ at room temp)

As you can see, density and viscosity are very dependent on the type of liquid.

There are also liquids (more properly suspensions) that become very viscous when a magnetic field is applied, but the density is not affected.

There are a large number of factors depending on what type of liquid you are looking at.

Hmm that's a bit of a funny topic. It really depends on whether the liquid you are talking about is purely metallic or a non-metal liquid. Or whether it is organic or in organic.

Though Cap's point is correct, you must take into consideration of how much of the liquid you have (per kg) and at what temperature you have them at. Honey and water, then Honey mercury comparisons. Honey is the most viscous, and has the highest boiling point.

Oh, OK.