Hotel Excelsior Opera

Currently, I have a reservation at Hotel Excelsior Opera. It's a 3 star hotel in the 9th in Paris. I know I know, I said I wanted to be more central (perhaps the 7th or 8th) but the 9th will have to do. From the reviews that I read, the neighborhood is really lively. It's close to the Galleries Lafayettes (shopping!) and close to the beautiful Garnier Opera House. The last time I was in Paris, I spent a few hours in the area, but not enough to really get the experience. Here's a photo:
Even though it's in the 9th, it's at the border and very close to Boulevard Haussman. Anyhoo, not that it matters. I'll be hoofing it most of the time anyway. I just want to be in a safe but lively neighborhood so I can venture out after dark and not feel scared. The hotel got 4/5 stars on Trip Advisor and 7.6/10 on Venere. It has the amenities that I need: wi-fi and a/c. The rooms look to be a decent size, but that doesn't matter much. I just need to be sure and e-mail the hotel that I want a non-smoking floor and as nice a view as possible. Here's the view I had last time:

Not much, is it?

Well, that's one thing taken care of (unless I find a better hotel and a better deal.)

Next thing I want to do is stamp out an itinerary. Since I'm going alone, I can do whatever I want! I don't have to check in with anyone else to see if what I want to do is ok. I already know I want to spend more time in the chic St. Germain district. I'd also like to roam around the Sorbonne if I'm allowed to. Lunch and people watching at Les Deux Magots is a must. I'd like to do the Louvre again but without trying to see it all. That is impossible to do in a day. Trust me. I tried. Musee d'Orsay is of course on the list. But I don't want to do the exact same thing I did last time. I didn't get to Sacre Coeur last time (sacrilige!) so I've gotta do that. I'm toying with the idea of Giverny, but it may be trying to cram too much in such a short time. Can anyone recommend any clubs or bars to hang? I've gotta experience the nightlife.