Overnight stay in London, recommendations?

[Jimmy No Hands]

Bought my girlfriend tickets to see Wicked at the Apollo on the 20th December, we were contemplating just getting the train down and back up instead of staying, but I'm quite fond of the idea of staying over for the night instead. Being from't north it's all a bit daunting and I fear for my wallet. Just wondered if anybody could suggest anything for me to have a look at before I trawl through TripAdvisor. Criteria wise;

Ideally free on site parking
Doesn't have to be dead central, happy to jump in a taxi or walk to the nearest tube station (whatever a 'tube' is)
Price wise, ideally like £120 max but less would be better

Just a decent place to get a good sleep and have some breakfast really.

Thank you!

[Jimmy No Hands]

Thank you all for the suggestions, going to take a look now.

[Jimmy No Hands]

tpp_uk said:

Tower Bridge - Guoman hotel is currently showing a price of £119 for the evening of the 20th - Parking under the hotel, but don't bother with that, Wapping High Street (it's a quiet road with no through traffic, don't worry) is free on the weekends (and where I leave the Elise). Nice bar overlooking the river and the bridge - only half a dozen stops from Tower Hill in to the West End. It's where I put most of my visitors. St. Katharine Docks is a lovely spot too, and loads of restaurants.

http://www.guoman.com/hotels/united_kingdom/london...

Is there a good chance of a space on Wapping High Street on a Saturday morning? Contemplating scrapping staying over and just parking for the day now to be honest.