I've got a tough choice to make and need some expert advice...

I have limited time in Rome, and because several items on my "must see" list are closed on Mondays, I can only fit in two of the following three:

Castel Sant'Angelo, Capitoline Museums, or Borghese Gallery.

Which 2 do I keep, and which one do I save for a (hopefully) future trip?

I'd vote for Castel Sant'Angelo & Borghese Gallery.

It might help people respond if they knew your interests and what you will have seen/done previously.

I agree with Degas. The views of Rome from Castel Sant'Angelo are amazing and the Borghese Gallery is just beautiful. I never made it to the Capitoline Museums. The Borghese is relatively small and can easily be done in under 2 hours. Have fun!

Definately the Borghese-it's small with a mighty collection.

Degas has it exactly. You won't be sorry if you skip the Capitoline museums. Seeing them another time will give you something to look forward to.

Buon Viaggio,
BC

Wot Degas said.

One more time! Castel S. Angelo and Borghese. CSA has such an interesting history, first a mausoleum for Hadrian and later papal apartments. We finished off our visit, with a glass of wine from the "snack bar" and shared some of our potato chips with a pigeon, while enjoying a great view of Rome.

Castel Sant'Angelo is definitely a must, including a walk on the bridge connecting the building to the city

HI
another vote for Borghese Gallery--I assume you know that there are timed admissions for two hour visits, and your hotel can reserve a slot for you.