I'm just back from 3 days there with my Slovak girlfriend. Its a city where an inside track is definitely advantageous because if I was on my own I wouldn't have seen half the stuff I did.
Firstly the weather should was around 35 C. There's a lovely lake just outside the city where you can enjoy the weather, not sure how to get there but I think its near the airport area.
Secondly I liked the the old town, the Jewish quarter, loads of nice shops and pubs, but expensive
Thirdly, the castle is being renovated, its still worth a trip to but you can't go inside. There's a museum there but its closed on Monday's
Lastly, I read on this website before I went that there's not too much to do because the city centre is small and the most of the place is covered in flats a la Ballymun. These flats are not attractive but they are not similar to council flats here. Professional people occupy them and I was surprised by the amount of BMW's and Mercs I saw there. MORE IMPORTANTLY on the ground floor of every complex there are restaurants, pubs and shops that are good quality and great value - 75 cents for a pint 5 euro for a good meal
But I would recommend going to Budapest or Vienna for a day, something which I didn't get around to.