I got given loads of baby bath/talc/baby lotion/baby shampoo as gifts when I had ds. I have never used the lotion talc or shampoo and only started using some of the baby bath at about 9 months ish (ds 22 months). I used metanium but only very occasionally, I'm lucky that ds hardly ever gets any nappy rash.
I still have piles of cotton wool left over from when He was a newborn as found it fairly useless for wiping up big messy bf poos, but I have friends who still use it so depends on you really.
A thermometer is a good idea, but tbh you really don't need too much stuff. I was like you, wanted to be really prepared but still have a cupboard full of infacol, dentinox, gripe water, saline drops, teething powders. I really didn't find any of it to be of any use so next time I will save my money.
I found dentinox shampoo to be good for cradle cap and olive oil (normal kitchen stuff) good for dry skin/massages. I have sudocreme but again have never really used it as ds skin doesn't seem sensitive, though I have friends who still use it at every nappy change.
I guess the moral of the story is it really will depend on your dc and how you want to do things. I wish is remembered that shops are still open after I gave birth and not stocked up quite so much.
Lansinoh is another thing I didn't use all that much of, tho it gets rave reviews on mn. Worth considering if you are planning to bf, but it is expensive! Plenty of breast pads too, I underestimated these.
I found the most useful stuff to be.... Biscuits, cake and plenty of meals in the freezer!
Sorry for the mammoth post, got a bit carried away and off topic there. 