I don't like hot drinks (have not tried much hot food yet) during a race. It can make my blood pressure drop, which makes me feel really bad. And hot food tends to stay in my stomach longer than cold food or drinks.

Even on cold days, I stick with cold, or maybe lukewarm drinks. The hot cups are great to warm up hands, though!

I dunno.  I have those conditions more often than other 'extreme' conditions.  I get hot in goretex and cold without it.  What are the right clothes?

Multiple thin layers work for me, like a long sleeve tech tee and zip up top.  I also find keeping my head warm makes a big difference with my overall temperature.  Water resistant clothing doesn't make any difference if it is really pouring and waterproof is not breathable.

Really it comes down to figuring out what is enough layers to let some but not all heat escape when you are soaking wet.