Csiga is a friendly, cozy café and restaurant with really nice cuisine, rather popular with local expats. A very nice place; not too big, but it always has a relaxed, laid-back atmosphere, and is a good place to visit with a not-too-large group of friends.
I can’t say I’ve tried everything on the menu, but what I’ve tasted so far has always been fine. If you’re going to stay in Budapest for a while, it’s worth checking back, as part of the menu – the one on the blackboard on the wall – sometimes changes.
They also have wi-fi, if you need it.