How to see the whole Budapest in a day?

Yeah, great, attempt to see one of the great cities of Europe in 39.5 hours.

Find the Chain Bridge. Walk around either end of it. There's enough there to burn most of the time you have alloted.

I would suggest since time is short, that you get on one of the city tour buses. They are called, Hop-on Hop-off. I believe they are a flat rate for several hours time and you can get off where you want to explore more and get on another bus to move on to the next site.

There are also some 2-3 hour guided bus tours.

that way you can get a general look at many things in the city even if they will be a blurr in your memory later, too much to see for only one days time.

The West End is just a shopping mall, not real great Hungarian food there.

There are many places to eat Hungarian food downtown on or near Vaci Utca, the main tourist walkway that runs parraell to the Danube river. You can also walk on either side of the river on the Korso, made for walking.

Not sure about the clubs but this site has leads.

www.budapestinfo.hu

There are also guided walking tours in the city.

I live in the city and see something new everyday so good luck.

Take a helicopter trip, you'll see most of the city in one go.

Other than that you'll need an alternate reality where a day is a week long.

As soon as you arrive in BP-- book up at the fast guide centre, when you will see a lot more in a shorter time than you could otherwise. They are not expensive.

Google Earth. BAM!