Which Gambit would you choose

I know gambits don't have that good of a reputation in professional chess. So, I have a question for you guys: if you had to choose one gambit to use in a professional chess tournament, which one would be your choice? Rules: it has to be a real gambit (queens gambit is not allowed as you don't actually lose a pawn) and you can also choose if you want to play a gambit for black or for white.

Budapest gambit (black)

Evans gambit (white) 

Ursurov gambit (white)

Preferred: Budapest gambit (black)

Can you choose to play the side that ACCEPTS the Gambit?  If so, Milner-Barry Gambit (Give me Black!)

Otherwise, there are lines in the Catalan where White gambits a pawn.

I like the Vienna gambit, specifically the oxford line.

Oh yeah the Vienna gambit, I like that too

Most Gambits are trash, but one that even super-GMs respect is the Marshall

Depends whether you look for respectable or fun/speculative. I think that Marshall, two knights With Na5, Benko and, provocatively l, the Scotch are very good openings up to high level (nb not scotch gambit but ordinary scotch defense where white also more or less has to lose a pawn if black goes for 4. ... Qh4. Given this is rarely played and the status of the scotch the gambit is probably very sound... ). For speculative play and becoming more resourceful and tactically sharp I like to play anything from Alterman gambit guides but also the Kings gambit , von Hennig Schara gambit and I think the Schliemann defense is a very active option against the Ruy Lopez. If that last one counts as a real gambit. Seems there are less options against d4 but the Albin counter gambit can’t be that bad at lower levels imho. 

I don't think that this is true at all. While some of the gambits popular in the 1800s like Kings gambit or Evans gambit are not that highly regarded there are many more modern gambits that are very respectable even at the highest level.

Apart from the Marshal gambit in the Ruy Lopez, that white most often declines these days, there are also for example

• Another Marshal gambit in the semi-slav 1. d4 d5 2. c4 e6 3. Nc3 c6 4. e4!? dxe4 5. Nxe4 Bb4+ 7. Bd2 Qxd4 8. Bxb4 Qxe4+ 9. Be2
• The anti-Moscov gambit in the semi-slav: 1. d4 d5 2. c4 c6 3. Nf3 Nf6. 4.Nc3 e6 5. Bg5 h6 6. Bh4 dxc4 7. e4 g5 8. Bg3 b5
• In the modern mainline of the QID there is 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. Qc2 c5 6. d5 exd5 7. cxd5 Bb7 8. Bg2 Nxd5 9. 0-0
• In the classical mainline of the QID there is 1 d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. 0-0 0-0 7. d5 exd5 8. Nh4, a favourite of young Kasparov and more recently Alpha Zero.

These are just few examples that quickly come to mind. I'm sure there are many more.

Nimzowitsch teaches that all gambits which capture away from the center should be declined.  As a rule, I don't accept them, I simply continue my development.  The hypermodern style is rarely encountered these days, however, and against classical players, gambits can be highly effective.

Before I went full hypermodern, a friend of mine showed me the potential of the Breyer variation of the King's Gambit (1. e4 e5 2. f4 exf4 3. Qf3), for which the computer-recommended reply Qh4+ fails to an avalanche of tactics.  I was able to win an exchange from Stockfish at depth 20 with it (it took just over 15 moves to do so, but each move in the sequence was natural and easy to find).  A mere mortal wouldn't work through the complications even that well.  Of course, I don't play e5 anymore, so it's a moot point now.

The focus of the forum would be playing the side which gambits a pawn, but it's totally okay if anyone wants to write about a terrible gambit they would like to play against in addition to a good one you would actually use.

That is really interesting, I've heard someone saying that it is really bad to gambit a pawn in the first few moves, as your opponent's position is not yet settled, but that it was pretty OK to do so later in the game. I guess those are examples of that. Also, would you put the Benko Gambit among those? I have heard a lot of people saying good things about it, despite it consisting of gambiting a pawn in the first few moves.

Queen's Gambit - the one that isn't a "true gambit" lol

Other than that - perhaps the Benko Gambit. Black gets a lot of lasting pressure on two files for one pawn.

I had never heard of the Urusov Gambit and it's win rate is not that bad. Seems dangerous.

This is for beginners, but I still use it from time to time. If White plays d4 then play e5. It's called the Englunds Gambit.

Ursurov starts with e4 e5 Bc4...

Yes... But not just the Russian players. If you think about it it's the only logical move

I play the Saemisch as White, but I think Black looks good psychologically after this sac. Objectively, I'd probably prefer White though. 

Hey, just to mess around a little; want to experiment with this Queen sac line against me? I'll be White and play into this line. We can make it unrated though. What time control would you prefer? I can't play bullet well for the life of me though lol I am okay with blitz or rapid - longer time preferred, but we could get more games in with 5 min blitz or something too.

Budapest and Benko and Albin not so good in my opinion. Also Smith Morra not so good RIP Ken Smith my friend.