I've heard that the Smith-Morra is good for a draw, and it allows you to steer the game along distinct lines that I believe avoid the mainstream of book openings. My own favorite reaction to the Sicilian is the Staunton-Cochrane Variation, but my thread about this variation stirred up a lot of controversy (http://www.chess.com/forum/view/chess-openings/staunton-cochrane-sicilian-my-quotsicilian-killerquot).
There is a major flaw in the Smith-Morra Gambit. When I played the Sicilian, I enjoyed the Chicago Defense (1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 e6 5.Nf3 d6 6.Bc4 a6 7.O-O b5), but Black can just as easily DECLINE the 2nd pawn, and he can virtually force a direct transposition to the c3-Sicilian, which is the main reason I do not advocate the Morra Gambit.
When I played the Sicilian, which I played mainly the Taimanov or the Scheveningen (via 2...e6), I can tell you what my take was on the various Sicilians I faced:
Open Sicilian (2.Nf3 and 3.d4) - One of the reasons why I prefer 1...e5, 1...c6, or 1...g6 as Black against 1.e4.
Closed Sicilian (2.Nc3 and 3.g3) - This line is EXCELLENT for blitz tournaments (game in 5 minutes). I have faced this in OTB blitz events and it drains your time, then you lose on some time scramble error. In long time controls, it's good enough for a draw or some occasional surprise use, but it's not a good solution for everyday use. Of course, against lower competition, like 1700, anything would work. 1.e4 c5 2.h4 might be ok.
c3-Sicilian (a.k.a. Alapin) - I find this line to be a complete joke. See my previous posts in this thread. Patience is the key for Black. This line can be annoying to say, Najdorf players that want instant clash and a major combat. The Taimanov and Scheveningen are more positional and the c3-Sicilian should never bother a player like this, myself included!
Grand Prix Attack (2.f4 or 2.Nc3 Nc6 3.f4) - The latter is better than the former. The former allows the Tal Gambit (2...d5 3.exd5 Nf6) or Toilet Variation (2...d5 3.Nc3), neither of which are any good for White. Throwing in 2.Nc3 Nc6 first before 3.f4 is a slight improvement, and it will get the unprepared, but those that know it, this line is not a problem at all for Black.
Morra Gambit (2.d4) - If White could force Black to accept, I might advocate it more than I do. There are trap lines, like the one with e6 and Qc7 by Black (can't think of the name of it, but 8.Qe2 is a blunder in that line). And I always liked the Chicago Defense, but it's not without its problems to solve as well. However, declining it and transposing to a c3-Sicilian is sure-fire equality at worst for Black, and why I wouldn't play it as White.
Wing Gambit (2.b4) - This line is horrible because of 2.cxb4 3.a3 d5!
Deferred Wing Gambit (2.a3 intending 3.b4) - This is what I play myself. See post 15 for sample games. I advocate this line because it's extremely tricky, and there is no refutation. Against correct play, it might only be equal, but the path to correct play against this is the width of a piece of thread while the path to equality against the Alapin is the width of the broad side of a barn!
Lines with 2.Nc3 and 3.Bb5 - These lines are fairly recent and can be tricky for Black to defend. Often times, they end up being very similar to the Hubner Variation of the Nimzo-Indian Defense with the colors reversed. If you like blocked positions with your main advantage being pawn structure, and can squeeze out very long endgames and win because of your opponent's structural damage, like doubled c-pawns, give this line a whirl.
Lines with 2.Nf3 and 3.Bb5 - The Moscow (2...d6 3.Bb5+) I don't think gets White much of anything. The Rossolimo (2...Nc6 3.Bb5) is a bigger problem for Black. He often has to deal with the same issues as in 2.Nc3 and 3.Bb5, though there are differences in the two lines. White can again squeeze out a small advantage via slow, methoical play, realizing that his trumps are long term and not blasts at the Black King.
So which lines do I respect for White and feel White can try to play for a win with?
Correspondence and Long Time Controls Over the board: Open Sicilian, Deferred Wing Gambit, Nc3/Bb5 lines, and the Rossolimo (2.Nf3 Nc6 3.Bb5)
Blitz events: Everything listed above for Correspondence and OTB events along with the Closed Sicilian.
I've heard that the Smith-Morra is good for a draw, and it allows you to steer the game along distinct lines that I believe avoid the mainstream of book openings. My own favorite reaction to the Sicilian is the Staunton-Cochrane Variation, but my thread about this variation stirred up a lot of controversy (http://www.chess.com/forum/view/chess-openings/staunton-cochrane-sicilian-my-quotsicilian-killerquot).