I've recommended Cafe Mode on here before. The person who went didn't like it and it gets mixed reviews here:
http://www.london-eating.co.uk/3324.htm
But I've been three times for my birthday, and other friends have had their birthdays there too. Barring the occasional scatty service we've always really enjoyed it. It's a sort of modern-European bistro, it's great value for money, and the location in Covent Garden is good. I've always found the staff lovely, even if they're rushed off their feet, and Mohammed (the owner) is a lovely bloke. I also think it has a really nice atmosphere.
I'll see if I can think of other places too...