I was there a bit over year ago with my brother. It was summer though (August) so I don't know what the weather will be like and what will be fun. But there's plenty to see, I was there just for 3 days so I most likely missed out on a lot.
Restaurants: I liked Fatal (Fátál or something like that - at least it wasn't fatal to me
) near the Vaci Utca. Matyas is a bit fancier, also close to the Vaci Utca. I'd recommend to reserve a table in both of those in the evenings, they aren't exactly well kept secrets.
Since it was over a year ago, I don't remember that much of it anymore - I'll have to go through the photos to see where I was and what I did.
I'll try to post some more recommendations later - during the weekend perhaps.
And here's some pics:
The Parliament:
Halaszbastion (Fishermen's Bastion):
And a church from the centrum, Szent István-bazilika (St Stephen's Basilica):
