Matsuri is nice, a teppanyaki restaurant and they have them all over London. I can thoroughly recommend the prawn tempura, steak teppanyaki and flaming icecream!
http://www.matsuri-restaurant.com/
Chair is also nice for a more general upmarket menu...http://www.urbanpath.com/london/british/chair-restaurant.htm.
The Mint Leaf is the place to be for an indian...http://www.london-eating.co.uk/3486.htm
Elysium at The Cafe Royal in Picadilly (round the corner from Chinawhite) is lovely to and a great night out depending on your budget.
Zilli fish is good for fish...http://www.zillialdo.com/intro2.htm.
For something a bit different and if you like Jazz, Ronnie Scott's is a great night out and they do food but best to book...http://www.ronniescotts.co.uk/.
If you have a big budget somewhere like Claridges goes down well...http://www.claridges.co.uk/restaurants_and_bars/default.asp.
Or try these...
http://www.london-eating.co.uk/
http://www.lastminute.com/site/entertainment/r estaurants/ - some good last minute deals.
Hope you have a good night x