So, all I’ve ever had is
A) the crap Martini and Rossi stuff, and
B) the completely different stuff that you drink cold by the glass from the tap in Spain.
Anything between these two poles? What to put in a martini? Is the stuff I drinkin Spain what vermouth SHOULD taste like, or is it a different animal? I’m so un-keen on the Martini/Rossi stuff that I usually just skip the vermouth and have. . . an exceedingly dry martini (i.e. gin in a glass). Please help.
Oh, to cross reference the gin thread. Sorry.
I no nothing about Vermouth. I have a bottle of Martini and Rossi dry and that is only for making Martini’s, which I don’t do often. But I would love to learn.
I’m no vermouth expert, but I have heard people say stay with French for dry and Italian for sweet. As I said in the other thread though, the variety of brands available in the US is pretty sparse, at least from what I’ve found.
No, you don’t.
Exactly 
As a general word of advice, make sure any vermouth you use is fresh. Yes, it’s fortified, but it’s still wine and it will go bad. Keep it in the fridge, and don’t be afraid to buy a fresh bottle every so often.
Re dry vermouth, Dale DeGroff speaks highly of Chambery. I’ve never had it, but I’d trust his advice.
If you happen to stumble across any bottles of King Eider, grab them all immediately, keep one for yourself, and sell the rest to me. This is not a joke; it’s no longer made, but it was fabulous stuff, and I’m willing to pay good money for it.
Re sweet vermouth, the best you can get is Carpano Antica. Highly, highly recommended. If you like sweet vermouth, you should also check out Punt Y Mes and other drinks based on fortified wine with herbs in it.
Re stuff you can realistically get, Vya makes both sweet and dry vermouth that are above average. You might want to check them out.
Oh, and for a martini recipe, scroll down to the series of recipes I posted in this thread.
This was excellent. Exactly what I was hoping for. Thanks.