Sistine Chapel

Yes, Sistine Chapel is the same as the Vatican Museums. The sistine Chapel is only accessible during a visit to the museums. You may have seen varying times because the Vatican Museums tend to vary the opening times based on the season, closing earlier in winter months. Also the last "entrance" time is usually an hour before closing time.

The last entrance time Ellen is referring to is the entrance to the museums. The Sistine Chapel is a bit of a trek from the entrance. The guards will start encouraging people to head towards exits long before 6 pm.

The Vatican seems to tweak hours and admission rules every year (first of January) and it appears 2010 is no exception so you can't go buy guidebooks because they are out of date (assuming you are going in 2010). Their schedule for 2010 lists last entrance at 4 pm, two hours before closing.
http://mv.vatican.va/3_EN/pages/z-Info/MV_Info_Calendario.html#cal2

In case it wasn't quite clear, the Sistine Chapel is IN the Vatican Museum, but a long trek (may take an hour to reach it from entrance of the museums depending on crowds).

I'll never forget that a friend, who went to the Vatican, told me he went to "THE SIXTEEN CHAPELS". It took me quite a while to determine that the clown meant "SISTINE CHAPEL".

hahah maybe it felt like 16 chapels?

i am aware that the sistine is in the vatican museum, but wasn't sure if it was closed earlier bc it was special. also, do you think it's a good idea to go to the basilica first and then the museum in the afternoon? (assuming that the museum closes @ 6 according to the vatican website).

Thanks for all the help... i'll be arriving in rome in ~2wks and am going to be a total tourist.

"do you think it's a good idea to go to the basilica first and then the museum in the afternoon? "

Why?

The museum entrance is over half a mile of dull walking from the entrance to St Peter's. But if you go into the museums first, and finish at the Sistine Chapel, you can take the staircase on your right as you leave the chapel (assuming your back's to the altar) which takes you more or less to the main entrance of St Peter's, still inside the secure area.

Doing it that way round (if you remember to take the correct staircase) avoids both the long, boring walk AND the queue for security at St Peter's - which is usually a great deal longer than the one for the museums.

Not the most important consideration in the world. But you don't say why you think either order might be a good idea. Your appreciation of the museums, BTW, will be unaffected by whether you've seen St Peter's or not

Sorry-my reasoning was spend the morning @St. Peter's/cupola, and wait for the line to die down at the vatican museums and then visit the museums after noon. Doesn't the St. peter's security line go pretty quickly though? St. Peter's won't affect the appreciation of the museums but it is part of the vatican city experience.. no?

There is no need to stand in line. Just book a ticket for the time you want on the Vatican website.
http://biglietteriamusei.vatican.va/musei/tickets/index.html

You can cut through the lines to the museums by pre-booking your ticket online- take your print-out confirmation sheet and just push through all the people standing in line and go over to the guards:

http://biglietteriamusei.vatican.va/musei/tickets/do?weblang=en&do

It might be preferable to visit the museums in the morning when you're fresh, and like flanner pointed out you can pretty much go directly to st peter's from the sistine chapel (and like he said make sure you exit through the door on the right- it might have a sign that says "tour groups only" on it that you should ignore)

Definitely skip the St. Peter's line by going to the Museum first, ending your tour in the Sistine Chapel. From there, go out the exit door at the back, on the right, and you will be able to walk directly to St. Peter's without going outside to wait in line and go through security. It is a huge time-saver.