Can't decide where I really would like to stay. What's it like in the Columbus Circle area? Is the upper Westside nicer to walk around than say Midtown? Will be all over and am going to the Bronx for Yankee games too. What is the Holiday Inn 57th Street Midtown area like? Any special tips or ideas
about what to expect if I go to the west side instead! Any favorites welcome also.

You'll do fine in the Columbus Circle area. Columbus Circle is at the SW corner of Central Park...great for walking in the spring. It's also near Lincoln Center, Columbus Avenue, etc., etc. The West 57th Street area (a couple blocks from Columbus Circle is a lively area. Also, it's a short walk to Rockefeller Center and Times Square areas. You're near a subway station and it's fairly convenient for getting to Yankee Stadium by subway.
Assuming you're coming to NY soon, you'll be here during a great time of the year wetherwise.

I would go to the Holiday Inn 57th Street.

Thanks Howard & Bob- I appreciate your help and now I'm all set. Will be there for a whole week in the middle of May and hope I hit some beautiful walking around weather. I got my Lion King tickets too! Will definitely go to Ellis Island- and wonder if you have ever been to the Cloisters? I've heard the time spent there is really worth it. Do you have any favorite stops or spots of your own? Do you think I can get an
"outside" big sky person to do the
Metropolitan. Could you spend a lot of time there or would it be worth trying to dash through? I'd like New Yorker's
opinion. If it's like the Art Institute in Chicago I bet it's a whole day at least. Are there a lot of impressionists?

Even a full day won't do justice to the Metropolitan but is a good start. Avoid going on a Saturday when crowds are enormous. If the "big sky" person is the restless sort, then park him or her at the Temple of Dendur area whil you browse paintings. It's a huge area devoted to a reassembled Egyptian temple and one entire wall of the room (the wall is probably at least 150 feet long by 50 or 60 feet high) is windows that look out onto Central Park. It's the most peaceful and conducive to contemplation of any place I've yet come across in NYC except for Fort Tryon park (where the Cloisters is located). Get a good box lunch to bring with you to the Cloister and enjoy the park with it's remarkable landscaping and view of the Hudson and the Palisades.

You've gotten some solid advice. Here (I hope) is some more.
1. First, the Metropolitan Museum. Yes, the Temple of Dendur is must. And, yes, the Met has a wonderful Impressionists collection. As far as size, the Met is much larger than the Art Institute of Chicago. If it's any help, the Met and the Art Institute are my two favorite US museums. And, as a previous poster said, don't even try to see it all in one day! But, it certainly is worth for the Temple and the Impressionists and whatever else you have time for. Since you will be in NYC for a week, I think you can "afford" to spend a day there.
2. The Cloisters is definitely worth a visit. It should be especially beautiful in May. (Spring is my favorite time in NYC.)
3. One of our favorites areas for walking is Soho, which is south of Greenwich Village (another good area for walking).
4. For other entertainment: If you like ballet (and since you'll be staying so close to Lincoln Center), you should consider attending a performance by either the American Ballet Theater or the New York City Ballet. Both are outstanding companies and both will be performing during your stay. If you want suggestions for other Broadway shows, I'll be happy to add other suggestions.
4. You'll be very moved by Ellis Island. An added bonus to the boatride is an excellent view of the Statue of Liberty. While you are down in Battery Park (where you get the boat to Ellis Island), I believe there is a new Holocaust Musuem in that area. Also, while in that area, you might want to go to the top of the World Trade Center, which on a clear day offers a better view than the Empire State Building.
5. And finally, you might want to go to the new Rose Center for Earth and Space at the Museum of Natural History (which is a mile walk north from Columbus Circle to see the new planetarium show and other exhibits. Warning: If you go, an afternoon visit is suggested, as I understand groups of schoolchildren go in the morning!

I was not impressed by the new astronomy wing at the museum of natural history. Maybe the planetarium show is worth it, and the rest physically is nice to look at but the substance was underwhelming.