What a coincidence. We just returned from two nights in Vegas, and we also saw "O" and Spamalot.  "O" was excellent - from start to finish, one of the best shows I've seen.  Spamalot was very clever - we enjoyed it quite a bit.Â

For dinner, I'd recommend Alex (in the Wynn).  This would fit really well with your plan to see Spamalot (which is also in the Wynn). We scheduled dinner at 6.00 pm, had the tasting menu, and walked over to Spamalot for the 8.00 pm showing.  The tasting menu would normally take about 2 - 3 hours, but they were very accommodating, and we were able to finish within 1 1/2 hours without feeling rushed.  If I were Michelin, I'd give the experience a very solid 2 stars.

For the second evening, we dined at L'Atelier after seeing the 7.30 pm show of "O".  We've been to L'Atelier in Paris about a half dozen times, so it's hard for us not to compare the two.  Although the service was more friendly in Vegas, the food was not as compelling.  The menu is different, which we expected, but the food seemed less interesting than the version in Paris.  My recommendation is to save L'Atelier for you next trip to Paris, but take a pass when in Vegas.

We had dinner last night at L'Atelier, and it was among the best meals we've ever had.  The 9 course tasting menu had a broad variety, and when we asked to change an item that we weren't crazy about trying, there was no question at all.  Service and pace were outstanding, and we weren't charged corkage when we  offered our server a glass of 96 Fisher Lamb that we brought.  We were also fortunate to strike up a conversation with the couple next to us, who shared a glass of 90 Montrose that they brought with them.  Made for a stupendous evening.