Doing a little bit of googling, contaminated ice can be a big problem. Bacteria and viruses can be transferred to stored ice, just the same as any food. I'm not sure how this compares to the contamination of water or drinking vessels, but I'm betting it's easier for harmful bacteria to spread around an ice container than it is to get around glasses or into water pipes.
Theoretically, ice water should be
less contaminated than room temperature (or freezer temperature) water. However, ice is often kept in (open) containers, which are rarely cleaned "because it's just water, it doesn't get dirty", while water is usually either from a tap (running water, so less bacteria etc) or from closed bottles.
I drink lots and lots and
lots of water, and I ahve bottels scattered throughout the house - but when I find a bottle that's been open a week or so, I give it to the plants because the bottle'll start smelling old and musty. Not dangerous or anything yet, but unpleasant.
Honestly - if you got your water from a bucket that had been standing open outside for a few days, you'd be disgusted. An ice bucket out in the open in a cooler box or something, next to a buffet? Nobody raises an eyebrow.
Anyway, I prefer my drinks on the temperature where their taste is optimal. Sodas/pops/whatever you call them, around 2°C-7°C (freezer or slightly colder). Bottom fermented beer, 6° to 8°. Top fermented beers, somewhere around 12°.
The colder something gets, the less you taste of it, because the cold numbs your taste receptors. Any type of beer saying you should drink it "freezing cold" (like most South American beers for example, which are tapped at below-freezing temperatures in frosted glasses, preferably) are actually saying "we taste like shit, but cold enough you'll just taste something slightly bitter and really cold, thus feeling refreshed". Of course, the opposite holds true as well (too warm and your taste buds are less sensitive too), and what temperature is ideal for what drink depends on which aromas you want to activate or to be more powerful. The same beer, 10° apart, can make for a very different taste sensation.