Is 1.e4 d5 an "ok" opening

That's his entire carreer, not what he's playing now.

If I select his black games since 2007 (in a database mostly made up of TWICs), I get 115 out of 227 games 1.e4, and in those he played 1...d5 69 times and 1...c5 46 times.

It's true that he used the Scandi against weaker players on average (2486 vs 2578), but I also recall him using it as his only weapon in one or two recent Corus tournaments. That's as top level as it gets, especially for Tiviakov.

In 2009 only, it's 30 Scandis vs 11 Sicilians, and opposition is more or less equal (2554 for the Scandi, 2540 for the Sicilian).

So he was probably using it against weaker players while he was learning it, and nowadays it is definitely his main weapon.

When Tiviakov started using the Scandinavian in 2005, he was ranked #20 in the world. Today he is #61. One wonders if the decision to abandon the Sicilian was a good one...

I remember the line now that I played against your move.  4...Nf6 was wrong on my part.

1.e4 d5 2.exd5 Nf6 3.Bc4 Nxd5 4.Nc3 Nb6 5.Bb3 Nc6 6.Nf3 Bf5 7.0-0 e6 8.d4 Be7 9.Bf4 0-0 and black has equality.

 hahah :) Corny chess-humor. I like it :D

What you really want t0 guard against is the Icelandic gambit 1.e4 d5 2.exd5 nf6 3.c4 e6.  Agressive opening for black.

I love it when black plays it against me! It is one of the few defenses I feel confident against.

Edit: Or competent!

 In my opinion the Sicilian was Tiviakov's ticket into the top 100, whereas the Scandinavian is his ticket out of the top 100. Tiviakov is a top 100 player using the Scandinavian at the moment - Scarblac is correct. However, it also matters HOW one gets to be an elite player, and the Scandinavian did not contribute to Tiviakov's success.

I don't know why we're discussing this -- your main point was that hardly any top GM uses the Scandinavian, and nobody disagrees. But you stated it slightly too strongly and now we're all discussing Tiviakov...

Tiviakov has had a long carreer, earning the GM title in 1991 and playing for Russia in the Olympiad in 1994. When I look at his Rating Progress chart at http://ratings.fide.com/id.phtml?event=1008013 (which has data since 2000 only), in 2004/5, his rating suddenly shot up from +- 2600 to +- 2700, staying on a higher level (in the 2630-2700 range) since. The graph refutes your case.

Anyway, Tiviakov may be boring but he's extremely practical. If he prefers the Scandi over the Sicilian now it's because it's giving him better results. Which in his terms probably means fewer losses with Black.

Huh? What case does the graph refute? Having one's ELO constant for a period of five years means that a player is losing strength relative to others due to ratings inflation. It is the same as with currency - 10k dollars ten years ago had greater buying power than 10k dollars today.

In fact the graph strengthens my case, as obviously up to 2005 Tiviakov made progress using the Sicilian, while after 2005 he struggled to keep the ratings level.

Again, 2005 is important due to the fact that Tiviakov adopted the Scandinavian for the first time against Stellwagen in the Dutch Championship.

Yes it is a good line

Although, if you want a new weapon, look into 3...Qe6+. It is a fun and dynamic line to play.

 3...Qe6+  makes it worse for Black since it blocks the e pawn along with the dark and light squared bishops.Black will have a hard time to find space and counterplay.

What if white declins the black pawn and moves to e5? So it looks like this: e4 d5, e5 d4, 

Black can play d4 there and it might be good, but also something like Bf5 and Black is playing French Defense without the bad Bishop or Caro-kann advance up a tempo depending how you want to think of it. This should be more than satisfactory for Black though you might surprise some opponents with the line in Blitz or something, also you can get into the Tennisson Gambit or maybe something Blackmar-Deimer like if you really don't want to take on d5, but taking on d5 seems obvious and best.

Something does occur to me with the Scandinavian that I don't think anyone mentioned.  In many openings against e4, Black aims to play a knockout d5 against e4 to open his game, bust the centre and loosen the White grip.  You are doing this at move 1.  Sure, the queen is brought out giving the knight a target for a natural developmental move but structurally has White not lost a little bit by the pawn's exchange?  For anyone who doesnt know what I am talking about, remember how often and for long that Black attempts to play d5 in the Sicilian as the freeing break.  Consider the freedom of the black knight to come to f6 unmolested once the e-pawn is gone.  Is the queen on a5 exploitable?  Not easily and she is at least off the back rank.  I would rather not be Black after a couple of moves in but it does not seem that deficient, particularly when your preparation is in that line more than your opponent's.