Valuables (Ring)

As a general rule, and as in the book/film The Accidental Tourist, I'd suggest not bringing anything you can't afford to lose. I would leave that ring at home and try one of your costume rings to keep your finger comfortable. Hopefully it would not be an issue, but there's no guarantee.

"I'd also appreciate any Russia-specific tips"

Learn the Cyrillic alphabet. If you do nothing else before your trip, do this. It will make everything MUCH easier, since you will be able to decode signs and sound out words. For instance, PECTOPAH is pronounced "restoran" and is, indeed, "restaurant."

I used the book Teach Yourself The Cyrillic Alphabet (it now appears to be out of print). This made it easy, as it broke it down into letter that are the same as English, letters that look the same but are pronounced differently, letters we don't have but sounds we do, etc.

St. Petersburg has a fair amount of English in the central section (the "tourist zone") with English menus and enough spoken English in restaurants and at museums to get the job done. I would assume that outside of this area, it's Russian or nothing (certainly the case outside of Moscow and St. Petersburg in general).

Make sure you visit the Russia Museum. The Hermitage is great, but it has stuff by artists you can see elsewhere. The Russia Museum has amazing things by Russian artists you won't see elsewhere; don't miss The Wave by Aivosovsky.

Make sure you visit the Yusupov Palace. I didn't get to Peterhof or the Catherine Palace, and they sound great but may be too blinged-out for my taste. But the Yusupov felt quite liveable (while still quite fancy); the little jewelbox of a theater inside the palace was wonderful.

If you have any interest in musical instruments or fancy mansions, or want to see something without crowds, go to the Sheremetyov Palace, which now houses a museum of musical instruments. The miniature violins and the armonica (not a typo; it's a glass harmonica) are still memorable to me, several years later, as is the Etruscan Room.

Other than that, your NYC skills will work well in St. Petersburg (taking the Metro, not showing your money in public, looking confident when you're going somewhere, etc).

Harold:
thanks for all the thoughtful advice. I will definitely use your tips! I'm excited about the musical instrument museum you mentioned, as well.

Laura:
I wasn't actually asking if I should bring valuables or a ring in a general way. Obviously, I'd rather not lose the ring, but it wouldn't be the end of the world. What I was wondering is how jewelry of that type is viewed by Russians and whether it would be a conspicuous thing to wear or not. I've heard conflicting reports about how diamond rings, even costume versions, are perceived in Russia and I wouldn't want to make myself a target of petty theft for no reason.

We have "travel rings", simple small gold bands, we can wear on the road without attracting undue attention to ourselves. In Russia, the cops are corrupt, you don't want to interact with them if you don't have to - wearing an expensive ring may result in a shakedown by the cops.

I didn't notice pickpocket activity in St. Petersburg; if there is anything to worry about, St. Petersburg is the most likely place to experience it, it has the most tourists and crowded tourist attractions.

Just my two cents: I wouldn't wear the ring not because its not safe but because you would be worried about it and it would take away from your trip.

Moscow and St. Petersburg are full of Russians who spend more per day than the cost of your ring...there are more Mercedes per square foot than in Germany...and Dolce & Gabbana has long established itself in city centers. We got into a conversation with a designed purse salesman in Milan - he prefers Russian tourists to all others because they spend money like no tomorrow. Russian people like wear designer jeans and expensive jewelry even to go to the store. But those people "walk the walk and talk the talk" and look comfortable doing it. So if you're ever robbed, it won't be because you have a ring but because you don't look confident.

Most of Russia is not rich of course, but if you stick to city center and tourist areas, you're likely to encounter the rich minority. If you're going outside those areas, its the opposite.

Another tip: Russian schools have a foreign language requirement from 1st grade and that language is usually English. So most youth (under 30) speak enough English to give you directions. Most people that work in subway/bus stations (who are older) do not. This is the opposite of how it works in Europe.

Also, someone above mentioned cop corruption. I believe the country has been cracking down on it recently, so don't assume corruption...aka offer bribes, give cash, etc. That's a good way to get arrested. There probably (certainly, lol) is corruption but it's not in the open and doesn't apply to tourists.

Hope this helps a bit :)