If nightlife is your goal, take a second look at the location of the LM Monaco. Monaco is not that large, but this hotel is some distance from the casino which is where I presume the clubs are clustered around.

We stayed in upgraded rooms on points as a Plat and those rooms were easily worth 300 Euros plus. The sea view from the hotel is beautiful, the private beach is very nice, it just doesn't have the St. Regis type service level and finish. Based on prices in comparable European locations Paris, Cannes, Rome etc.. 300 Euros is fair enough. Monaco is an expensive destination. There may be an event on that date driving up prices.