hey there!
I'm a Hungarian, moved to Geneva 3 months ago. Here are some facts and advice
* divided by the Danube into Buda and Pest, the calm, greener part and the throbbing, lively part respectively.* I would advise to choose a hotel or hostel on the Pest side, altough it is busier and more noisy but transportation is much better and you'll be in a walking distance to the best places* for a long weekend I would go for the following spots: Day one: Buda Side - Gellért Spa, Buda Castle, Fishermen's Bastion, Citadella, Philisopher's garden (bring a book and a few beers and chill)Day two: Pest Side - Heroes square, Museum of Terror, Museum of Fine Arts (all three in the same area), City center, Vaci street (shopping), Parlament (world's biggest parlament), Basilica
For the night if you would like to go out:
drinking, hanging out: Godor (means Hole), the best place for youngsters, it's is in the middle of the city center on Deak Ferenc Square (main square for transport, all underground lines meet here). It's a frigging huge hole in the ground to where you can bring your own booze or just buy it there. Almost everyone hits the Hole during an evening, it's  a must.All the other great places are in the vicinity of the Hole, mainly on Kiràly street (King street) and Dob street (Drum street). Liszt Ferenc square is also worth checking but it's a bit posh.
dancing: Nagymezo street, not far from the Hole and the Western Train station. This street is packed with clubs. The better ones: B7, Soho, New Orleans, Moulin RougeBUT: the problem is that there is a new law which prohibits clubs and pubs from being open after 10 in the evening but only in district 6, unfortunately that is our bohemian district.
So if you want to dance go to Dokk Beach. It's on the Shipyard Island and there are 6-7 clubs next to each other: Slager (70s-90s), Cafe Puerto (salsa, latin), Dokk (rnb, disco), Bed (electro), Studio (electro), Dokkolo (electro, hits)
Just call a cab or hop into a cab and tell them Dokk beach through Arpad Bridge. From the city center it should not cost more than 10EUR
general info:
* when asking for information go to the young people, they speak english. the older generation is more familiar with german or russian. 
* the one and only rule for foreginers who visit budapest: never ever argue with security!!!! you'll end up badly beaten in your own blood. also, don't go to places to where you were invited by strangers (like people asking for help then taking you to a club etc.) cuz you will get a bill of 1000EUR for a bottle of champagne. 
* if your plan to travel a lot it's worth buying a budapest weekend card with which you can travel freely on every public transport line and you will also get discounts in museums and sightseeing bus trips.
your main transportaion will be the 4-6 tramline (might be the busiest in europe) and the underground lines. 
* controllers on buses and trams are NOT allowed to touch you or restrain you or touch your ID card. never give them anything!
hope i helped a bit. you will love the city. after london, bp is the best place to party
cheers,N
nolan, Sep 11, 2009 @ 15:25

 This is excellent! :) I am also going to BP, but next Friday for a long week-end! Great info! :)
I am so looking forward to be there!
Have a good week-end!
Ludmila
Ludmila, Sep 11, 2009 @ 18:56

Nolan, super tips!!!! thanks!

Ludmila, have a great weekend in BP!! looking forward to your extra tips soon!
wudiana, Sep 11, 2009 @ 21:09

 I just saw your note, but I was there for one week about 3 weeks ago, (after my previous visit 6 years ago) and I can tell you that I got an excellent deal with Swiss Air out of Geneva (129 CHF round trip) I stayed at Hotel Charles, excellent room and great staff 45 Euro for a big room/appartment with kitchen, transport system, buses metro just great and easy to use, I do recommend the Budapest card which will also give you discounts at museums and restaurants, by the way, restaurants are great, incidentally I found an authentic Mexican restaurant there (No Tex-Mex), I only took public transport in the city, other than the airport authorized transfer,but I was advised by the always kind staff at the hotel that it was better to call a taxi than to take one at the street, and yes, while walking at Vacii Utca I was approached by two girls trying to engage in conversation and take me to a bar (typical scam I have read about since years ago and ....never go to Galaxia, bar,,,,, I have read about it but this scam is targeted to men more than girls) and hey prices are just great (I mean compared to Switzerland)  Hey another plus is a great place for dental care at dental fees much lower than in Switzerland
Hungarian people are great, and despite my basic Hungarian phrases I found that people would speak english,, (I was more amazed at an old store clerk who always kind had the basic english),, It never hurts to learn some basic Hungarian phrases,,,, 
Enjoy Budapest,,,,,,!!!!
DeepSoul, Sep 15, 2009 @ 20:52

thanks deep soul and reka for the detailed information! now I'm just wonderin 3 days would be enough... : )

I'm flying with swiss air too...great deal... better schedule and cheaper than easyjet, amazing!

wudiana, Sep 16, 2009 @ 22:58

 Hi, me I am Hungarian too and there is probably one thing I would add to the list, if you like fun, there is a labyrinth beneath the Buda Castle, check out the website and decide yourself if worth visiting:

http://www.labirintus.com/en

Otherwise have a very good time!

MEdit, Sep 16, 2009 @ 23:49

 Hello, I will also be in Budapest on a solo trip from Oct 8 to Oct 12. Thanks everyone for the suggestions. It will be my first trip to Hungary and I am so excited to experience the local culture.
Scott M, Sep 24, 2009 @ 01:10